信息系统和数据库中英文对照外文翻译文献
Web信息系统毕业论文中英文资料外文翻译文献
Web信息系统毕业论文中英文资料外文翻译文献中英文资料翻译With the popularity of the Inter NET applications, a variety of Web Information System Has become a pressing issue. Establish the essence of Web information systems Development of a Web repository (database as the core of a variety of Web letter Information storage) as the core Web applications. Currently, the Web repositorydevelopment technologyOperation of a wide range of different characteristics. Various periods at all levels, a variety of purposes Technology co-exist, dizzying mirror chaos, it is difficult to choose. More popular Java of Ser vet Web repository development program a more practical Of choice.Servlet is running the applet on the Web server, can be completed Xu Multi-client Applet can not complete the work, which runs on the server and clients No end, do not download do not by the client security restrictions, the running speed Greatly increasedAnd Applet running in a browser and extend the browser's ability similar Like, Serv the let run in the Web server to enable Java Serv the let engine And expand the capacity of the server. Therefore, we can say Serv the let is run in Applet on a Web server, Serv the let Jav a Ser vlet API And Jav a program of classes and packages.1 Servlet access model2 Serv the let, there are three access models:(1) an access model1 browser to Web server to issue a retrieval request.2 the Web server after receipt of the request, the requestforwarded tothe Servle tengine.3 Serlet engine to perform the requested the Ser vlet and directly throughJDBC4Servlet throughJDBC toretrieve searchresults to generate the html page and Page back to the Web server.5 the Web server the page is sent back to the browser.(2)The second access model1 browser to Web server to issue a retrieval request.2 the Web server receives the request after the request forwardedto the of Ser v the letengine.3 Serv let engine to perform the request the the Ser vlet and retrieve sentJa, vabean access to the data.4data access the Ja vabean searchable database throughJDBC informationAnd from the search results stored in itself.5Servlet remove search results from the data access Javabean generate Html page and Ht ml of page back to the w eb server.6 the Web server the page is sent back to the browser.(3) The third access model1 A browser issue a retrieval request to the Web server.2 Web server receives the request after the request forwarded to the ofSer v the let engine.Of Ser vlet engine to perform the requested Servlet directlythroughJDBC inspection3 The cable database and search results are stored in the result isstored the Jav abean into.Javabean,4. Ser v the let from the results are stored to remove the search results and JSP files to format the output page.2 Servlet functionality and life cycle2.1Servlet functions(1) Create and return dynamic Web pages based on customer requests.(2) create can be embedded into existing HTML pages as part of HTML Page (HT fragment) of the ML.(3) and other server resources (including databases and applications based on the Jav a Program) to communicate.(4) to handle multiple client connections, receiving the input of more than one client, and The results broadcast to multiple clients. For example, Ser vlet is a multi-participant Game server.(5) of MIM E type filter information on the special handling, such as image Conversion and server-side include (SSI).(6) custom processing available to all servers in the standard routine.2.2Servlet lifecycleServlet life cycle begins with it into the Web server's memory And end in the termination or re-loaded Serv the let.(1) load.Load the servlet at the following times:1. If you have configured automatic load option, and then start the Webserver automatically loaded2.After the start of the Web server, the client Serv the let issued for the first time, pleaseDemand.3.Reload Serv the let.Loaded Servlet, Web servers to create a servlet instance, and Servlet's init () method is called. Servlet initialization parameters in the initialization phase, The number is passed to the Servlet configuration object.(2) terminateWhen the Web server no longer needs the servlet, or reload Servlet A new instance of the server calls Serv the let's destroy () method, remove it from the Memory deleted.3 How to call ServletMethod of Ser vlet is called Total five kinds: call in the URL in the formT ag call, call, in HT the ML page in the JSP files Call, call in an ASP file. The following itemized to be introduced.(1) call the servlet in the URL.Simply input format in the browser as http: ∥yo ur webser ver the same the ser vlet name name / servlet path / servlet the URL to The site canbe. Ofwhich:your webser ver name is to refer to the Servlet where theWeb server name, the servlet path is the path refers to the Servlet, the servletThe name refers to the Servlet real name or an alias.(2) call the Servlet tagsCall of Ser the let the the tag allows users to input data on the Web page, andinput data submitted to the vlet of Ser.Serv the let will be submitted to receive data in different ways.For example: {place the text input area tags, buttons and other logos} (3) in the HTML page to call the servlet.Use mark tags, no need to create a complete HTML page.Instead,the servlet output isonly part of the HTMLpage (HTML fragment) and dynamicallyembedded into the static text in the original HTML page.All this happened on the server andsent to the user only the resulting HTML page. tag contained in the original HTML page.Servlet will be invoked in these two markers and the Ser vlet response will cover these two markersbetween all things and mark itself, for example: 〈SERVLET NAME= “my serv let ”CODE= “my serv let .class”CODEBASE= “u r l”initpar am= “v alue”〉〈PARAM NAME= “parm1”VALU E= “v alue1”〉〈PARAM NAME= “parm2”VALU E= “v alue2”〉〈/SERVLET 〉(4) call the servlet in the JSP files.Call in the JSP file format used by the Servlet and HTML page to call exactly the same.Andthe principles are identical. Only reconcile its dynamic JSP file is not a static HTML page.(5) in an ASP file calls the servlet.If you Micr oso ft I nt ernet Informatio n-Ser ver (II S) on the legacy of the ASP file, and can not be ASP files transplanted into a JSP file, you can use the ASP file to of Ser vlet iscalled.But it must be through a special ActiveX control, an ASP file is only through it can callthe servlet.4 Servlet Howto use ConnectionManager toefficiently manage the database connection (1) the functionality of the Connection Manager.For non-Web applications, Web-based application access tothe database will lead tohigher and unpredictable overhead, which is due to more frequent Web users connect anddisconnect.Normally connected to the resourcesused and disconnect from the databasewill farexceed the resources used in the retrieval.Connection Manager function is to minimize the additional occupancy of the users of the database resources to achieve thebest performance of database access.Connection Manager sharing overhead through the establishmentof the connection poolwill connect users Servlet available to multipleusers request.In other words, each userrequest only the connect/ disconnect with a small portion of the overhead costs.Initialresources to establish the connection of the buffer pool, the rest of the connect/ disconnectoverhead is not big, because this isonly reuse the existing connection.Serv the let in the following manner using the connectionpool: When a user throughRequest Web Serv the let the let Serv use an existing connection from the buffer poolNext, this means that the user requests do not cause the connection to the databasesystem overhead. InAfter the termination of serv the let it connect to return to the pool forits Connection ManagerThe Ser vlet. Thus, the user request does not cause the database is disconnectedOf system overhead.Connection Manager also allows users to be able tocontrol the concurrency of thedatabase products evenThen the number. When the database license agreement limit the number ofusers, this feature isVery useful. Create a buffer pool for the database, and connection managementBuffering pool "maximum number of connections" parameter setto the database product license limitGiven maximum number of users. If you use otherprograms without Connection ManagerconnectionsDatabase, you can not guarantee that the method is effective.(2) the structure of the Connection Manager.(3) Connection Manager connection pool to maintain a connection to a specificdatabase is open. Step 1: When the first Serv the let trying to Connection Manager communications is loaded by the Java Application ServerConnection Manager. As long as the Java application server running the Connection Manager has been loaded. Step 2: The Java application server passes the request to a servlet. Step 3: Servlet Connection Managerrequests a connection from the pool. Step four: the buffer pool to Ser vlet allocated a pool of existing idle connection. Step 5: servlet to use toconnect a direct dialogue with the database, this process is the standard API for a particular database. Step 6: the database through Ser vlet the connection returns data. Step 7: When theServlet end to communicate with the database, servlet connections returned to the connection manager pool for other servlet uses. Step 8: Servlet Jav a application server to the user sends back response.Servlet requests a connection, if the buffer pool, there is no idle connection, then the connection manager directlycommunicate with the database. Connection Manager will: Step 9: to the database requests a new connection. Step 10: Add connections to thebuffer pool. If the buffer pool is connected to the prescribed ceiling, connect to the serverWill not be a new connection to join the buffer pool(3) the performance characteristics of the Connection Manager.Buffer pool to create a new connection is a high overhead tasks, newconnections will use the resources on the database. Therefore, theConnection Manager the best use of existing connections of the buffer pool to meet the request of the Servlet. Meanwhile, the connecting tubeThe processor must be as much as possible to minimize the buffer pool idle connections, because this is a great waste of systemresources. Connection Manager Serv the let with the implementation of these minimize and maximize task. Connection Manager to maintain each connection verification time stamp, and recently used tags and use the logo. When the a Ser vlet first the connection, connection verification time stamp, and most recent time stamp is set to the current time, theconnection is being used flag is set to true.Connection Manager can be removed from a Serv the let a long-unused connections, this length of time specified by the Connection Manager, the longest cycleparameters.Connection Manager can view recently used mark is beingused to connect. If the time between the most recently used time and time difference is greater than the longest cycle configuration parameters, the connection will be considered to be a residual connection, which indicates Serv the let take its discontinued or no response. Residual connection will be returned to the pool for other Ser vlet, it is being used flag is set to false, authentication and time stamp is set to the current time.If Ser vlet is ready within a longer period of time to use the connection with the database several timesCommunications, you must code to the Serv the let, so that each time you use to connectConfirm that it still occupies this connection.Connection Manager can be removed from the buffer pool idle connections, because theyWould be a waste of resources. In order to determine which connection is idle, Connection Manager will checkInvestigation connected the sign and time stamp, this operation isconnected by periodic access toBuffer pool information. Connection Manager checks have not been any Ser vlet makeWith the connections (these connections is to use the logo is false). If you have recently usedBetween time and the current time difference exceeds amaximum idle time configuration parameters, theThat the connection is idle. Idle connection will be removed from the buffer pool, down toMinimum number of connections configuration parameter specifies thelower limit value.翻译：随着Inter net 的普及应用, 各种Web 信息系统的建立已成为一个迫在眉睫的问题。
数据库中英文对照外文翻译文献
中英文对照外文翻译Database Management SystemsA database (sometimes spelled data base) is also called an electronic database , referring to any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval , modification, and deletion of data in conjunction with various data-processing operations .Databases can be stored on magnetic disk or tape, optical disk, or some other secondary storage device.A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage , and each field typically contains information pertaining to one aspect or attribute of the entity described by the database . Using keywords and various sorting commands, users can rapidly search , rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregate of data.Complex data relationships and linkages may be found in all but the simplest databases .The system software package that handles the difficult tasks associated with creating ,accessing, and maintaining database records is called a database management system(DBMS).The programs in a DBMS package establish an interface between the database itself and the users of the database.. (These users may be applications programmers, managers and others with information needs, and various OS programs.)A DBMS can organize, process, and present selected data elements form the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or poorly defined ,but people can “browse” through the database until they have the needed information. In short, the DBMS will “manage” the stored data items and assemble the needed items from the common database in response to the queries of those who aren’t programmers.A database management system (DBMS) is composed of three major parts:(1)a storage subsystemthat stores and retrieves data in files;(2) a modeling and manipulation subsystem that provides the means with which to organize the data and to add , delete, maintain, and update the data;(3)and an interface between the DBMS and its users. Several major trends are emerging that enhance the value and usefulness of database management systems;Managers: who require more up-to-data information to make effective decisionCustomers: who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts.Users: who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages.Organizations : that discover information has a strategic value; they utilize their database systems to gain an edge over their competitors.The Database ModelA data model describes a way to structure and manipulate the data in a database. The structural part of the model specifies how data should be represented(such as tree, tables, and so on ).The manipulative part of the model specifies the operation with which to add, delete, display, maintain, print, search, select, sort and update the data.Hierarchical ModelThe first database management systems used a hierarchical model-that is-they arranged records into a tree structure. Some records are root records and all others have unique parent records. The structure of the tree is designed to reflect the order in which the data will be used that is ,the record at the root of a tree will be accessed first, then records one level below the root ,and so on.The hierarchical model was developed because hierarchical relationships are commonly found in business applications. As you have known, an organization char often describes a hierarchical relationship: top management is at the highest level, middle management at lower levels, and operational employees at the lowest levels. Note that within a strict hierarchy, each level of management may have many employees or levels of employees beneath it, but each employee has only one manager. Hierarchical data are characterized by this one-to-many relationship among data.In the hierarchical approach, each relationship must be explicitly defined when the database is created. Each record in a hierarchical database can contain only one key field and only one relationship is allowed between any two fields. This can create a problem because data do not always conform to such a strict hierarchy.Relational ModelA major breakthrough in database research occurred in 1970 when E. F. Codd proposed a fundamentally different approach to database management called relational model ,which uses a table asits data structure.The relational database is the most widely used database structure. Data is organized into related tables. Each table is made up of rows called and columns called fields. Each record contains fields of data about some specific item. For example, in a table containing information on employees, a record would contain fields of data such as a person’s last name ,first name ,and street address.Structured query language(SQL)is a query language for manipulating data in a relational database .It is nonprocedural or declarative, in which the user need only specify an English-like description that specifies the operation and the described record or combination of records. A query optimizer translates the description into a procedure to perform the database manipulation.Network ModelThe network model creates relationships among data through a linked-list structure in which subordinate records can be linked to more than one parent record. This approach combines records with links, which are called pointers. The pointers are addresses that indicate the location of a record. With the network approach, a subordinate record can be linked to a key record and at the same time itself be a key record linked to other sets of subordinate records. The network mode historically has had a performance advantage over other database models. Today , such performance characteristics are only important in high-volume ,high-speed transaction processing such as automatic teller machine networks or airline reservation system.Both hierarchical and network databases are application specific. If a new application is developed ,maintaining the consistency of databases in different applications can be very difficult. For example, suppose a new pension application is developed .The data are the same, but a new database must be created.Object ModelThe newest approach to database management uses an object model , in which records are represented by entities called objects that can both store data and provide methods or procedures to perform specific tasks.The query language used for the object model is the same object-oriented programming language used to develop the database application .This can create problems because there is no simple , uniform query language such as SQL . The object model is relatively new, and only a few examples of object-oriented database exist. It has attracted attention because developers who choose an object-oriented programming language want a database based on an object-oriented model. Distributed DatabaseSimilarly , a distributed database is one in which different parts of the database reside on physically separated computers . One goal of distributed databases is the access of informationwithout regard to where the data might be stored. Keeping in mind that once the users and their data are separated , the communication and networking concepts come into play .Distributed databases require software that resides partially in the larger computer. This software bridges the gap between personal and large computers and resolves the problems of incompatible data formats. Ideally, it would make the mainframe databases appear to be large libraries of information, with most of the processing accomplished on the personal computer.A drawback to some distributed systems is that they are often based on what is called a mainframe-entire model , in which the larger host computer is seen as the master and the terminal or personal computer is seen as a slave. There are some advantages to this approach . With databases under centralized control , many of the problems of data integrity that we mentioned earlier are solved . But today’s personal computers, departmental computers, and distributed processing require computers and their applications to communicate with each other on a more equal or peer-to-peer basis. In a database, the client/server model provides the framework for distributing databases.One way to take advantage of many connected computers running database applications is to distribute the application into cooperating parts that are independent of one anther. A client is an end user or computer program that requests resources across a network. A server is a computer running software that fulfills those requests across a network . When the resources are data in a database ,the client/server model provides the framework for distributing database.A file serve is software that provides access to files across a network. A dedicated file server is a single computer dedicated to being a file server. This is useful ,for example ,if the files are large and require fast access .In such cases, a minicomputer or mainframe would be used as a file server. A distributed file server spreads the files around on individual computers instead of placing them on one dedicated computer.Advantages of the latter server include the ability to store and retrieve files on other computers and the elimination of duplicate files on each computer. A major disadvantage , however, is that individual read/write requests are being moved across the network and problems can arise when updating files. Suppose a user requests a record from a file and changes it while another user requests the same record and changes it too. The solution to this problems called record locking, which means that the first request makes others requests wait until the first request is satisfied . Other users may be able to read the record, but they will not be able to change it .A database server is software that services requests to a database across a network. For example, suppose a user types in a query for data on his or her personal computer . If the application is designed with the client/server model in mind ,the query language part on the personal computer simple sends the query across the network to the database server and requests to be notified when the data are found.Examples of distributed database systems can be found in the engineering world. Sun’s Network Filing System(NFS),for example, is used in computer-aided engineering applications to distribute data among the hard disks in a network of Sun workstation.Distributing databases is an evolutionary step because it is logical that data should exist at the location where they are being used . Departmental computers within a large corporation ,for example, should have data reside locally , yet those data should be accessible by authorized corporate management when they want to consolidate departmental data . DBMS software will protect the security and integrity of the database , and the distributed database will appear to its users as no different from the non-distributed database .In this information age, the data server has become the heart of a company. This one piece of software controls the rhythm of most organizations and is used to pump information lifeblood through the arteries of the network. Because of the critical nature of this application, the data server is also the one of the most popular targets for hackers. If a hacker owns this application, he can cause the company's "heart" to suffer a fatal arrest.Ironically, although most users are now aware of hackers, they still do not realize how susceptible their database servers are to hack attacks. Thus, this article presents a description of the primary methods of attacking database servers (also known as SQL servers) and shows you how to protect yourself from these attacks.You should note this information is not new. Many technical white papers go into great detail about how to perform SQL attacks, and numerous vulnerabilities have been posted to security lists that describe exactly how certain database applications can be exploited. This article was written for the curious non-SQL experts who do not care to know the details, and as a review to those who do use SQL regularly.What Is a SQL Server?A database application is a program that provides clients with access to data. There are many variations of this type of application, ranging from the expensive enterprise-level Microsoft SQL Server to the free and open source mySQL. Regardless of the flavor, most database server applications have several things in common.First, database applications use the same general programming language known as SQL, or Structured Query Language. This language, also known as a fourth-level language due to its simplistic syntax, is at the core of how a client communicates its requests to the server. Using SQL in its simplest form, a programmer can select, add, update, and delete information in a database. However, SQL can also be used to create and design entire databases, perform various functions on the returned information, and even execute other programs.To illustrate how SQL can be used, the following is an example of a simple standard SQL query and a more powerful SQL query:Simple: "Select * from dbFurniture.tblChair"This returns all information in the table tblChair from the database dbFurniture.Complex: "EXEC master..xp_cmdshell 'dir c:\'"This short SQL command returns to the client the list of files and folders under the c:\ directory of the SQL server. Note that this example uses an extended stored procedure that is exclusive to MS SQL Server.The second function that database server applications share is that they all require some form of authenticated connection between client and host. Although the SQL language is fairly easy to use, at least in its basic form, any client that wants to perform queries must first provide some form of credentials that will authorize the client; the client also must define the format of the request and response.This connection is defined by several attributes, depending on the relative location of the client and what operating systems are in use. We could spend a whole article discussing various technologies such as DSN connections, DSN-less connections, RDO, ADO, and more, but these subjects are outside the scope of this article. If you want to learn more about them, a little Google'ing will provide you with more than enough information. However, the following is a list of the more common items included in a connection request.Database sourceRequest typeDatabaseUser IDPasswordBefore any connection can be made, the client must define what type of database server it is connecting to. This is handled by a software component that provides the client with the instructions needed to create the request in the correct format. In addition to the type of database, the request type can be used to further define how the client's request will be handled by the server. Next comes the database name and finally the authentication information.All the connection information is important, but by far the weakest link is the authentication information—or lack thereof. In a properly managed server, each database has its own users with specifically designated permissions that control what type of activity they can perform. For example, a user account would be set up as read only for applications that need to only access information. Another account should be used for inserts or updates, and maybe even a third account would be used for deletes.This type of account control ensures that any compromised account is limited in functionality. Unfortunately, many database programs are set up with null or easy passwords, which leads to successful hack attacks.译文数据库管理系统介绍数据库（database,有时拼作data base）又称为电子数据库，是专门组织起来的一组数据或信息，其目的是为了便于计算机快速查询及检索。
信息与计算科学中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)【Abstract】Under the network environment the library information resource altogether constructs sharing is refers to all levels of each kind of library basis user to the social information demand, through network use computer, correspondence, electron, multimedia and so on advanced information technology, the high idealization carries on the synthesis cooperation development and the use activity to various collections information resource and the network resources . The market economy swift and violent development, the networking unceasing renewal, the information age arrival, had decided the future library trend of development will be implements the information resource altogether to construct sharing, already achieved the social mutual recognition about this point.This is because:libraries implement the information resource altogether to construct sharing are solve the knowledge information explosion and the collection strength insufficient this contradictory important way..【Key Words】Network; libraries implement: information: construction；work environment the libraryUnder the network environment the library information resource altogether constructs sharing is refers to all levels of each kind of library basis user to the social information demand, through network use computer, correspondence, electron, multimedia and so on advanced information technology, the high idealization carries on the synthesis cooperation development and the use activity to various collections information resource and the network resources.1、 information resource altogether will construct sharing is the future library development and the use information resource way that must be taken.The market economy swift and violent development, the networking unceasing renewal, the information age arrival, had decided the future library trend of development will be implements the information resource altogether to construct sharing, already achieved the social mutual recognition about this point.This is because: 。
信息管理与信息系统论文中英文资料外文翻译文献
信息管理与信息系统论文中英文资料外文翻译文献Construction of Network Management Information System of Agricultural Products Supply Chain Based on 3PLsAbstractThe necessity to construct the network management information system of 3PLs agricultural supply chain is analyzed, showing that 3PLs can improve the overall competitive advantage of agricultural supply chain. 3PLs changes the homogeneity management into specialized management of logistics service and achieves the alliance of the subjects at different nodes of agricultural products supply chain. Network management information system structure of agricultural products supply chain based on 3PLs is constructed, including the four layers (the network communication layer, the hardware and software environment layer, the database layer, and the application layer) and 7 function modules (centralized control,transportation process management, material and vehicle scheduling, customer relationship, storage management, customer inquiry, and financial management).Framework for the network management information system of agricultural products supply chain based on 3PLs is put forward. The management of 3PLs mainly includes purchasing management, supplier relationship management, planning management, customer relationship management, storage management and distribution management. Thus, a management system of internal and external integrated agricultural enterprises is obtained. The network management information system of agricultural products supply chain based on 3PLs has realized the effective sharing of enterprise information of agricultural products supply chain at different nodes, establishing a long-term partnership revolving around the 3PLs core enterprise, as well as a supply chain with stable relationship based on the supply chain network system, so as to improve the circulation efficiency of agricultural products, and to explore the sales market for agricultural products.Key words3PLs (third party logistics)，Agricultural products supply chain, Network management information system, China3PLs means that production enterprises entrust the logistics activity to the professional logistics service firms in order to concentrate efforts on core business, to keep close contact with logistics enterprise through information system, and to achieve a logistics operation and management mode with full control in logistics. According to the 3PLs requirements forinformation technology, supply chain management information system based on 3PLs is a supply chain management mode with 3PLs enterprises as the core, using EDI technology, GIS/GPS system, B/S mode and other technologies. Integration, processing and application of 3PLs enterprises in supply chain management information system are fully applied in order to reduce the cost of logistics and to improve the service level of logistics.At present, management information technology in China is just at the initial stage. The existing management information system offers insufficient information for the 3PLs enterprises which are engaged in the circulation of agricultural products.Besides, its construction of logistics data processing system is imperfect, having not realized the truly professional 3PLs enterprises for the circulation of agricultural products with information technology. At the same time, 3PLs enterprise for agricultural products has just started in China. And logistics applied in the agricultural supply chain with 3PLs enterprise as the core is time-consuming, inefficient and low-level, which can hardly meet the needs of the rapid development of rural market and social productive forces. Therefore, it is particularly important and urgent to construct a management information system for agricultural products supply chain under the current Internet environment. Problems in the management of the supply chain of agricultural products are analyzed, and a network management information system of agricultural products supply chain based on 3PLs is constructed in order to offer references for the information management in the supply chain of agricultural products in China.1 Necessity of constructing the network management information system of agricultural products supply chain based on 3PLsAgricultural products are seasonal, perishable and vulnerable. With the improvement of income level，consumers have increasingly high requirements for the diversification, personalization, just-in-time nature, and environment protection of agricultural products, which requires faster, more professional，and better organized logistics. At the same time, supply chain of agricultural products has the characteristics of the special purpose of funds, the uncertainty of market, and the unbalanced development of market. Thus, the support of supply chain management information system is needed during the circulation of agricultural products. Construction of market integration,as well as the integration of production, supply and marketing,urgently needs a new management information system of agricultural products, as well as an accompanying legal support system, in order to reduce the cost and to increase the profit for agricultural enterprises. And the application of 3PLs in the supply chain of agricultural products can solve this problem.Therefore, we should give full play to the central hub function of 3PLs enterprises in agricultural products supply chain, increase the input in the informationization of agricultural products supply chain, and promote the construction of logistics operation system and management information system.1 .1 Improving the overall competitive advantage of agricultural products supply chain by 3PLs3PLs is a new logistics organizational form established by modern information technology, as well as a kind of complementary and win-win strategic alliance by signing contract with the party being served. Taking 3PLs as the professional and core enterprise in the production and circulation of agricultural products can help to realize resource consolidation of the construction and organization of the whole supply chain of agricultural products. The specialization of raw materials and the service for product distribution have greatly improved the logistics efficiency of traditional enterprise. At the same time, construction of the management information system ofagricultural products supply chain based on 3PLs has made up for the shortage of information in agricultural market, has improved the efficiency of the flow of agricultural products, has connected all the links in the supply chain into an organic whole in an reasonable and effective way,and has enhanced the overall competitive advantage and economic benefits. 3PLs platform has greatly brought down the production and circulation processes of traditional agricultural enterprises, and has reduced the costs in raw material procurement and product distribution, so as to better adapt to the changes in market demand, to realize the rational distribution of resources, and to improve the overall competitiveness of the supply chain of agricultural products.1 .2 Changing the homogeneity management to specialized operation of logistics service by 3PLsDue to the characteristics of agricultural products, market requirement for logistics varies widely. Since traditional enterprises try to obtain the competitive advantage, there is fierce market competition in commodity circulation. Therefore, behavior of logistics market shows the characteristics of homogeneity and the profit is getting lower and lower. In order to seize the customer, some enterprises even take a loss. 3PLs enterprises share business risk with partners and carry out operation according to the items number, time and cost of customer by integration and utilization of resources. As a means of the supply chain integration of agricultural products, specialized operation of 3PLs can help the stakeholders of supply chain to obtain more demand information of agricultural products, and can reduce the circulation cost of agricultural products.1 .3 Alliance of the subjects in supply chain nodes of agricultural products by 3PLs3PLs stresses the relationship of “mutual complementarity, benefit sharing, information sharing” among the stakeholders in different nodes of supply chain. Development of the agricultural producer, supplier and retailer is limited if they rely only on their own resources. 3PLs enters into the outside service market, integrates the resources through the way of strategic alliances, ensures that the subject focuses its attention on core business, reduces the cost by scale effect, enhances the anti-risk strength, and helps to achieve quick response to market demand by information sharing.At the same time, contract-0riented 3PLs enterprises unify the interests of all subjects in supply chain of agricultural products, emphasize the strategic partnership of both parties,and alleviate market competition of related industries in agricultural markets. Subjects in both downstream and upstream of the supply chain share information and establish long-term partnership with 3PLs enterprises as the core.2 Construction of the network management information system of agricultural supply chain based on 3PLs2.1 Construction of structural system3PLs platform is used to offer network communications and system services to the subjects in agricultural supply chain. Fig. 1 illustrates the structural system of network management information system of agricultural supply chain based on 3PLs.Fig.1 Structural system of network management information system of agricultural supplychain based on 3PLsFig. 1 illustrates that the basic hardware of the system is combined by the network transmission media and network equipment, that is the network communication layer. Hardware facilities, corresponding system software, operation system and netmanager software together constitute the software and hardware environment layer.This layer provides necessary software and hardware facilities for 3PLs enterprises during the data storage and management of agricultural products. Database layer is responsible for the management of data source in agricultural information resources and network systems, and offers data integration to the application layer. 3PLs standard system includes the overall standard, network infrastructure standard, application support standard, application standard, information security standard, and management standard. Safety system of 3PLs includes the security management, security infrastructure, and security service.This system is composed of 7 function modules, such as the centralized control module, transportation process management module, material and vehicle scheduling module, customer relationship module, storage management module, customer query module, and financial management module(Fig. 2),the function of which is to ensure the information fluency and system security of 3PLs enterprises during the operation and integration of resources. These modules have improved the service module of different nodes in agricultural supply chain and have reduced the operation risk of system, so that the system becomes more structured, perfect, and rational.2.2 Framework of management systemBased on the existing research result，the business and module of modern logistics management，and the management information systems，Fig.3 reports the management system of internal and external integrated agricultural enterprises according to the circulation of agricultural products from the manufacturer，supplier，and retail terminal to the consumer.Fig．2 Function modules of 3PLs network management information systemFig.3 The management system of internal and external integrated agricultural enterprises Fig.3 shows the framework of network management information system of agricultural supply chain based on 3PLs. The whole system, running under an open 3PLs, is formed by four layers of network communication layer, software and hardware environment layer, database layer and application layer. In the application layer, 3PLs, as the core of management information system of agricultural supply chain, plays the role of information processing center. It mainly manages the plan, inventory, and other subsystems, supervises subsystem through supplier relationship, conducts information interaction with procurement management subsystem and the supplier, and carries out information interaction with the supplier, producer and consumer through customer relationship management subsystem and sales management subsystem. Besides, 3PLs is also responsible for logistics management and control through the distribution management subsystem. Management of 3PLs mainly includes the 7 modules of purchasing management, supplier relationship management, planning management, customer relationship management, sales management, inventory management and distribution management. Through the effectiveintegration and coordination between 3PLs and the business with partner at the downstream and upstream of agricultural supplier chain, management system of internal and external integrated agricultural enterprises is formed using the logistics information system to realize the integration of logistics and information flow.In general，3PLs enterprise is still in the initial stage in China. Management information system of agricultural supply chain is not perfect, which can not meet the current needs of the rapid development and agricultural products circulation in rural China. Thus, there is an urgent need to build a new mode of agricultural logistics, so as to reduce the process of sales turnover, to lower the production cost of 3PLs enterprises, to improve the circulation efficiency of agricultural products, and to expand the sales market of agricultural products.3 ConclusionDeveloping modern 3PLs is an inevitable trend of market development. Design and development of management information system based on 3PLs can bring spillover benefits to the producer, supplier and retailer of agricultural products.Under the current Internet environment, management information system of agricultural supply chain based on 3PLs must be established based on the specific characteristics of operation mode and the actual business situation of 3PLs enterprises, so as to establish a management information system suitable for a given enterprise. From the perspective of overall integration of resources, the network management information system of agricultural supply chain based on 3PLs established has connected the interests of different nodes in agricultural supply chain into an organic whole, has effectively eliminated the barriers to information flow, and has increased the profits of agriculture-related enterprises and farmers. At the same time, according to the characteristics of agricultural enterprises in China, a rational agricultural products logistics mode of internal and external integrated agricultural enterprise is established, which offers a reference for the management of agricultural supply chain in China.基于第三方物流的农产品供应链网络管理信息系统的建设摘要本文对构建网络农业第三方物流供应链管理信息系统的必要性进行了分析，表明第三方物流可以提高农产品供应链的整体竞争优势。
数据采集系统中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)Data Acquisition SystemsData acquisition systems are used to acquire process operating data and store it on，secondary storage devices for later analysis. Many or the data acquisition systems acquire this data at very high speeds and very little computer time is left to carry out any necessary, or desirable, data manipulations or reduction. All the data are stored on secondary storage devices and manipulated subsequently to derive the variables ofin-terest. It is very often necessary to design special purpose data acquisition systems and interfaces to acquire the high speed process data. This special purpose design can be an expensive proposition.Powerful mini- and mainframe computers are used to combine the data acquisition with other functions such as comparisons between the actual output and the desirable output values, and to then decide on the control action which must be taken to ensure that the output variables lie within preset limits. The computing power required will depend upon the type of process control system implemented. Software requirements for carrying out proportional, ratio or three term control of process variables are relatively trivial, and microcomputers can be used to implement such process control systems. It would not be possible to use many of the currently available microcomputers for the implementation of high speed adaptive control systems which require the use of suitable process models and considerable online manipulation of data.Microcomputer based data loggers are used to carry out intermediate functions such as data acquisition at comparatively low speeds, simple mathematical manipulations of raw data and some forms of data reduction. The first generation of data loggers, without any programmable computing facilities, was used simply for slow speed data acquisition from up to one hundred channels. All the acquired data could be punched out on paper tape or printed for subsequent analysis. Such hardwired data loggers are being replaced by the new generation of data loggers which incorporate microcomputers and can be programmed by the user. They offer an extremely good method of collecting the process data, using standardized interfaces, and subsequently performing the necessary manipulations to provide the information of interest to the process operator. The data acquired can be analyzed to establish correlations, if any, between process variables and to develop mathematical models necessary for adaptive and optimal process control.The data acquisition function carried out by data loggers varies from one to 9 in system to another. Simple data logging systems acquire data from a few channels while complex systems can receive data from hundreds, or even thousands, of input channels distributed around one or more processes. The rudimentary data loggers scan the selected number of channels, connected to sensors or transducers, in a sequential manner and the data are recorded in a digital format. A data logger can be dedicated in the sense that it can only collect data from particular types of sensors and transducers. It is best to use a nondedicated data logger since any transducer or sensor can be connected to the channels via suitable interface circuitry. This facility requires the use of appropriate signal conditioning modules.Microcomputer controlled data acquisition facilitates the scanning of a large number of sensors. The scanning rate depends upon the signal dynamics which means that some channels must be scanned at very high speeds in order to avoid aliasing errors while there is very little loss of information by scanning other channels at slower speeds. In some data logging applications the faster channels require sampling at speeds of up to 100 times per second while slow channels can be sampled once every five minutes. The conventional hardwired, non-programmable data loggers sample all the channels in a sequential manner and the sampling frequency of all the channels must be the same. This procedure results in the accumulation of very large amounts of data, some of which is unnecessary, and also slows down the overall effective sampling frequency. Microcomputer based data loggers can be used to scan some fast channels at a higher frequency than other slow speed channels.The vast majority of the user programmable data loggers can be used to scan up to 1000 analog and 1000 digital input channels. A small number of data loggers, with a higher degree of sophistication, are suitable for acquiring data from up to 15, 000 analog and digital channels. The data from digital channels can be in the form of Transistor- Transistor Logic or contact closure signals. Analog data must be converted into digital format before it is recorded and requires the use of suitable analog to digital converters (ADC)．The characteristics of the ADC will define the resolution that can be achieved and the rate at which the various channels can be sampled. An in-crease in the number of bits used in the ADC improves the resolution capability. Successive approximation ADC's arefaster than integrating ADC's. Many microcomputer controlled data loggers include a facility to program the channel scanning rates. Typical scanning rates vary from 2 channels per second to 10, 000 channels per second.Most data loggers have a resolution capability of ±0.01% or better, It is also pos-sible to achieve a resolution of 1 micro-volt. The resolution capability, in absolute terms, also depends upon the range of input signals, Standard input signal ranges are 0-10 volt, 0-50 volt and 0-100 volt. The lowest measurable signal varies form 1 t, volt to 50, volt. A higher degree of recording accuracy can be achieved by using modules which accept data in small, selectable ranges. An alternative is the auto ranging facil-ity available on some data loggers.The accuracy with which the data are acquired and logged-on the appropriate storage device is extremely important. It is therefore necessary that the data acquisi-tion module should be able to reject common mode noise and common mode voltage. Typical common mode noise rejection capabilities lie in the range 110 dB to 150 dB. A decibel (dB) is a tern which defines the ratio of the power levels of two signals. Thus if the reference and actual signals have power levels of N, and Na respectively, they will have a ratio of n decibels, wheren＝10 Log10（Na /Nr）Protection against maximum common mode voltages of 200 to 500 volt is available on typical microcomputer based data loggers.The voltage input to an individual data logger channel is measured, scaled and linearised before any further data manipulations or comparisons are carried out.In many situations, it becomes necessary to alter the frequency at which particu-lar channels are sampled depending upon the values of data signals received from a particular input sensor. Thus a channel might normally be sampled once every 10 minutes. If, however, the sensor signals approach the alarm limit, then it is obviously desirable to sample that channel once every minute or even faster so that the operators can be informed, thereby avoiding any catastrophes. Microcomputer controlledintel-ligent data loggers may be programmed to alter the sampling frequencies depending upon the values of process signals. Other data loggers include self-scanning modules which can initiate sampling.The conventional hardwired data loggers, without any programming facilities, simply record the instantaneous values of transducer outputs at a regular samplingin-terval. This raw data often means very little to the typical user. To be meaningful, this data must be linearised and scaled, using a calibration curve, in order to determine the real value of the variable in appropriate engineering units. Prior to the availability of programmable data loggers, this function was usually carried out in the off-line mode on a mini- or mainframe computer. The raw data values had to be punched out on pa-per tape, in binary or octal code, to be input subsequently to the computer used for analysis purposes and converted to the engineering units. Paper tape punches are slow speed mechanical devices which reduce the speed at which channels can be scanned. An alternative was to print out the raw data values which further reduced the data scanning rate. It was not possible to carry out any limit comparisons or provide any alarm information. Every single value acquired by the data logger had to be recorded eventhough it might not serve any useful purpose during subsequent analysis; many data values only need recording when they lie outside the pre-set low and high limits.If the analog data must be transmitted over any distance, differences in ground potential between the signal source and final location can add noise in the interface design. In order to separate common-mode interference form the signal to be recorded or processed, devices designed for this purpose, such as instrumentation amplifiers, may be used. An instrumentation amplifier is characterized by good common-mode- rejection capability, a high input impedance, low drift, adjustable gain, and greater cost than operational amplifiers. They range from monolithic ICs to potted modules, and larger rack-mounted modules with manual scaling and null adjustments. When a very high common-mode voltage is present or the need for extremely-lowcom-mon-mode leakage current exists（as in many medical-electronics applications），an isolation amplifier is required. Isolation amplifiers may use optical or transformer isolation.Analog function circuits are special-purpose circuits that are used for a variety of signal conditioning operations on signals which are in analog form. When their accu-racy is adequate, they can relieve the microprocessor of time-consuming software and computations. Among the typical operations performed are multiplications, division, powers, roots, nonlinear functions such as for linearizing transducers, rimsmeasure-ments, computing vector sums, integration and differentiation, andcurrent-to-voltage or voltage- to-current conversion. Many of these operations can be purchased in available devices as multiplier/dividers, log/antilog amplifiers, and others.When data from a number of independent signal sources must be processed by the same microcomputer or communications channel, a multiplexer is used to channel the input signals into the A/D converter.Multiplexers are also used in reverse, as when a converter must distribute analog information to many different channels. The multiplexer is fed by a D／A converter which continually refreshes the output channels with new information.In many systems, the analog signal varies during the time that the converter takes to digitize an input signal. The changes in this signal level during the conversion process can result in errors since the conversion period can be completed some time after the conversion command. The final value never represents the data at the instant when the conversion command is transmitted. Sample-hold circuits are used to make an acquisition of the varying analog signal and to hold this signal for the duration of the conversion process. Sample-hold circuits are common in multichannel distribution systems where they allow each channel to receive and hold the signal level.In order to get the data in digital form as rapidly and as accurately as possible, we must use an analog/digital (A/D) converter, which might be a shaft encoder, a small module with digital outputs, or a high-resolution, high-speed panel instrument. These devices, which range form IC chips to rack-mounted instruments, convert ana-log input data, usually voltage, into an equivalent digital form. The characteristics of A/D converters include absolute and relative accuracy, linearity, monotonic, resolu-tion, conversion speed, and stability. A choice of input ranges, output codes, and other features are available. The successive-approximation technique is popular for a large number ofapplications, with the most popular alternatives being the counter-comparator types, and dual-ramp approaches. The dual-ramp has been widely-used in digital voltmeters.D/A converters convert a digital format into an equivalent analog representation. The basic converter consists of a circuit of weighted resistance values or ratios, each controlled by a particular level or weight of digital input data, which develops the output voltage or current in accordance with the digital input code. A special class of D/A converter exists which have the capability of handling variable reference sources. These devices are the multiplying DACs. Their output value is the product of the number represented by the digital input code and the analog reference voltage, which may vary form full scale to zero, and in some cases, to negative values.Component Selection CriteriaIn the past decade, data-acquisition hardware has changed radically due to ad-vances in semiconductors, and prices have come down too; what have not changed, however, are the fundamental system problems confronting the designer. Signals may be obscured by noise, rfi，ground loops, power-line pickup, and transients coupled into signal lines from machinery. Separating the signals from these effects becomes a matter for concern.Data-acquisition systems may be separated into two basic categories:（1）those suited to favorable environments like laboratories -and（2）those required for hostile environments such as factories, vehicles, and military installations. The latter group includes industrial process control systems where temperature information may be gathered by sensors on tanks, boilers, wats, or pipelines that may be spread over miles of facilities. That data may then be sent to a central processor to provide real-time process control. The digital control of steel mills, automated chemical production, and machine tools is carried out in this kind of hostile environment. The vulnerability of the data signals leads to the requirement for isolation and other techniques.At the other end of the spectrum-laboratory applications, such as test systems for gathering information on gas chromatographs, mass spectrometers, and other sophis-ticated instruments-the designer's problems are concerned with the performing of sen-sitive measurements under favorable conditions rather than with the problem ofpro-tecting the integrity of collected data under hostile conditions.Systems in hostile environments might require components for wide tempera-tures, shielding, common-mode noise reduction, conversion at an early stage, redun-dant circuits for critical measurements, and preprocessing of the digital data to test its reliability. Laboratory systems, on the other hand, will have narrower temperature ranges and less ambient noise. But the higher accuracies require sensitive devices, and a major effort may be necessary for the required signal /noise ratios.The choice of configuration and components in data-acquisition design depends on consideration of a number of factors:1. Resolution and accuracy required in final format.2. Number of analog sensors to be monitored.3. Sampling rate desired.4. Signal-conditioning requirement due to environment and accuracy.5. Cost trade-offs.Some of the choices for a basic data-acquisition configuration include：1 ．Single-channel techniques.A. Direct conversion.B. Preamplification and direct conversion.C. Sample-hold and conversion.D. Preamplification, sample-hold, and conversion.E. Preamplification, signal-conditioning, and direct conversion.F. Preamplification, signal-conditioning, sample-hold, and conversion.2. Multichannel techniques.A. Multiplexing the outputs of single-channel converters.B. Multiplexing the outputs of sample-holds.C. Multiplexing the inputs of sample-holds.D. Multiplexing low-level data.E. More than one tier of multiplexers.Signal-conditioning may include:1. Radiometric conversion techniques.B. Range biasing.D. Logarithmic compression.A. Analog filtering.B. Integrating converters.C. Digital data processing.We shall consider these techniques later, but first we will examine some of the components used in these data-acquisition system configurations.MultiplexersWhen more than one channel requires analog-to-digital conversion, it is neces-sary to use time-division multiplexing in order to connect the analog inputs to a single converter, or to provide a converter for each input and then combine the converter outputs by digital multiplexing.Analog MultiplexersAnalog multiplexer circuits allow the timesharing of analog-to-digital converters between a numbers of analog information channels. An analog multiplexer consists of a group of switches arranged with inputs connected to the individual analog channels and outputs connected in common（as shown in Fig. 1）．The switches may be ad-dressed by a digital input code.Many alternative analog switches are available in electromechanical and solid-state forms. Electromechanical switch types include relays, stepper switches,cross-bar switches, mercury-wetted switches, and dry-reed relay switches. The best switching speed is provided by reed relays（about 1 ms）．The mechanical switches provide high do isolation resistance, low contact resistance, and the capacity to handle voltages up to 1 KV, and they are usually inexpensive. Multiplexers using mechanical switches are suited to low-speed applications as well as those having high resolution requirements. They interface well with the slower A/D converters, like the integrating dual-slope types. Mechanical switches have a finite life, however, usually expressed innumber of operations. A reed relay might have a life of 109 operations, which wouldallow a 3-year life at 10 operations/second.Solid-state switch devices are capable of operation at 30 ns, and they have a life which exceeds most equipment requirements. Field-effect transistors（FETs）are used in most multiplexers. They have superseded bipolar transistors which can introduce large voltage offsets when used as switches.FET devices have a leakage from drain to source in the off state and a leakage from gate or substrate to drain and source in both the on and off states. Gate leakage in MOS devices is small compared to other sources of leakage. When the device has a Zener-diode-protected gate, an additional leakage path exists between the gate and source.Enhancement-mode MOS-FETs have the advantage that the switch turns off when power is removed from the MUX. Junction-FET multiplexers always turn on with the power off.A more recent development, the CMOS-complementary MOS-switch has the advantage of being able to multiplex voltages up to and including the supply voltages. A±10-V signal can be handled with a ±10-V supply.Trade-off Considerations for the DesignerAnalog multiplexing has been the favored technique for achieving lowest system cost. The decreasing cost of A/D converters and the availability of low-cost, digital integrated circuits specifically designed for multiplexing provide an alternative with advantages for some applications. A decision on the technique to use for a givensys-tem will hinge on trade-offs between the following factors:1. Resolution. The cost of A/D converters rises steeply as the resolution increases due to the cost of precision elements. At the 8-bit level, the per-channel cost of an analog multiplexer may be a considerable proportion of the cost of a converter. At resolutions above 12 bits, the reverse is true, and analog multiplexing tends to be more economical.2. Number of channels. This controls the size of the multiplexer required and the amount of wiring and interconnections. Digital multiplexing onto a common data bus reduces wiring to a minimum in many cases. Analog multiplexing is suited for 8 to 256 channels; beyond this number, the technique is unwieldy and analog errors be-come difficult to minimize. Analog and digital multiplexing is often combined in very large systems.3. Speed of measurement, or throughput. High-speed A/D converters can add a considerable cost to the system. If analog multiplexing demands a high-speedcon-verter to achieve the desired sample rate, a slower converter for each channel with digital multiplexing can be less costly．4. Signal level and conditioning. Wide dynamic ranges between channels can be difficult with analog multiplexing. Signals less than 1V generally require differential low-level analog multiplexing which is expensive, with programmable-gain amplifiers after the MUX operation. The alternative of fixed-gain converters on each channel, with signal-conditioning designed for the channel requirement, with digital multi-plexing may be more efficient.5. Physical location of measurement points. Analog multiplexing is suitedfor making measurements at distances up to a few hundred feet from the converter, since analog lines may suffer from losses, transmission-line reflections, and interference. Lines may range from twisted wire pairs to multiconductor shielded cable, depending on signal levels, distance, and noise environments. Digital multiplexing is operable to thousands of miles, with the proper transmission equipment, for digital transmission systems can offer the powerful noise-rejection characteristics that are required for29 Data Acquisition Systems long-distance transmission.Digital MultiplexingFor systems with small numbers of channels, medium-scale integrated digital multiplexers are available in TTL and MOS logic families. The 74151 is a typical example. Eight of these integrated circuits can be used to multiplex eight A/D con-verters of 8-bit resolution onto a common data bus.This digital multiplexing example offers little advantages in wiring economy, but it is lowest in cost, and the high switching speed allows operation at sampling rates much faster than analog multiplexers. The A/D converters are required only to keep up with the channel sample rate, and not with the commutating rate. When large numbers of A/D converters are multiplexed, the data-bus technique reduces system interconnections. This alone may in many cases justify multiple A/D converters. Data can be bussed onto the lines in bit-parallel or bit-serial format, as many converters have both serial and parallel outputs. A variety of devices can be used to drive the bus, from open collector and tristate TTL gates to line drivers and optoelectronic isolators. Channel-selection decoders can be built from 1-of-16 decoders to the required size. This technique also allows additional reliability in that a failure of one A/D does not affect the other channels. An important requirement is that the multiplexer operate without introducing unacceptable errors at the sample-rate speed. For a digital MUX system, one can determine the speed from propagation delays and the time required to charge the bus capacitance.Analog multiplexers can be more difficult to characterize. Their speed is a func-tion not only of internal parameters but also external parameters such as channel, source impedance, stray capacitance and the number of channels, and the circuit lay-out. The user must be aware of the limiting parameters in the system to judge their ef-fect on performance.The nonideal transmission and open-circuit characteristics of analog multiplexers can introduce static and dynamic errors into the signal path. These errors include leakage through switches, coupling of control signals into the analog path, and inter-actions with sources and following amplifiers. Moreover, the circuit layout can com-pound these effects.Since analog multiplexers may be connected directly to sources which may have little overload capacity or poor settling after overloads, the switches should have a break-before-make action to prevent the possibility of shorting channels together. It may be necessary to avoid shorted channels when power is removed and a chan-nels-off with power-down characteristic is desirable. In addition to the chan-nel-addressing lines, which are normally binary-coded, it is useful to have inhibited or enable lines to turn all switches off regardless of the channel being addressed. This simplifies the external logic necessary to cascade multiplexers and can also be useful in certain modes of channeladdressing. Another requirement for both analog and digital multiplexers is the tolerance of line transients and overload conditions, and the ability to absorb the transient energy and recover without damage.数据采集系统数据采集系统是用来获取数据处理和存储在二级存储设备，为后来的分析。
1外文文献：信息系统开发和数据库开发
Information System Development and Database DevelopmentIn many organizations, database development from the beginning of enterprise data modeling, data modeling enterprises determine the scope of the database and the general content. This step usually occurs in an organization's information system planning process, it aims to help organizations create an overall data description or explanation, and not the design of a specific database. A specific database for one or more information systems provide data and the corporate data model (which may involve a number of databases> described by the organization maintaining the scope of the data. Data modeling in the enterprise, you review of the current system, the need to support analysis of the nature of the business areas, the need for further description of the abstract data, and planning one or more database development project. Figure 1 shows PineValley furniture company's enterprise data model of a part.1.1 Information System ArchitectureAs shown in figure 1, senior data model is only general information system architecture (ISA> or a part of an organization's information system blueprint. In the information system planning, you can build an enterprise data model as a whole information system architecture part. According to Zachman (1987>, Sowa and Zachman (1992> views of an information system architecture consists of the following six key components:Data (Figure 1 shows, but there are other methods that>.Manipulation of data processing (of a data flow diagram can be used, with the object model methods, or other symbols that>.Networks, which organizations and in organizations with its main transmission of data between business partners (it can connect through the network topology map and to demonstrate>. People who deal with the implementation of data and information and is the source and receiver (in the process model for the data shows that the sender and the receiver>.Implementation of the events and time points (they can use state transition diagram and other means.>The reasons for the incident and data processing rules (often in the form of text display, but there are also a number of charts for the planning tools such as decision tables>.1.2 Information EngineeringInformation systems planners in accordance with the specific information system planning methods developed information system architecture. Information engineering is a popular and formal methods. Information engineering is a data-oriented creation and maintenance of the information system. Information engineering is because the data-oriented, so when you begin to understand how the database is defined by the logo and when information engineering a concise explanation is very helpful. Information Engineering follow top-down planning approach, in which specific information systems from a wide range of information needs in the understanding derived from (for example, we need about customers, products, suppliers, sales and processing of the data center>, rather than merging many detailed information requested ( orders such as a screen or in accordance with the importation of geographical sales summary report>. Top-down planning will enable developers to plan more comprehensive information system, consider system components provide an integrated approach to enhance the information system and the relationship between the business objectives of the understanding, deepen their understanding of information systems throughout the organization in understanding the impact.Information Engineering includes four steps: planning, analysis, design and implementation. The planning stage of project information generated information system architecture, including enterprise data model.1.3 Information System PlanningInformation systems planning objective is to enable IT organizations and the business strategy closely integrated, such integration for the information systems and technology to make the most of the investment interest is very important. As the table as a description, information engineering approach the planning stage include three steps, we in the follow-up of three sections they discussed.1. Critical factors determining the planningPlanning is the key factor that organizational objectives, critical success factors and problem areas. These factors determine the purpose of the establishment of planning and environment planning and information systems linked to strategic business planning. Table 2 shows the PineValley furniture company's key planning a number of possible factors, these factors contribute to the information systems manager for the new information systems and databases clubs top priority to deal with the demand. For example, given the imprecise sales forecasts this problem areas, information systems managers in the organization may be stored in the database additional historical sales data, new market research data and new product test data.2. The planning organizations set targetsOrganizations planning targets defined scope of business, and business scope will limit the subsequent analysis and information systems may change places. Five key planning targets as follows:● organizational units in the various sectors.● organizations location of the place of business operations.●functions of the business support organizations handling mission of the relevant group. Unlike business organizations function modules, in fact a function can be assigned to various organizations modules (for example, product development function is the production and sale of the common responsibility of the Ministry>.● types of entities managed by the organization on the people, places and things of the major types of data.● Information System data set processing software applications and support procedures.3. To set up a business modelA comprehensive business model including the functions of each enterprise functional decomposition model, the enterprise data model and the various planning matrix. Functional decomposition is the function of the organization for a more detailed decomposition process, the functional decomposition is to simplify the analysis of the issue, distracted and identify components and the use of the classical approach. PineValley furniture company in order to function in the functional decomposition example in figure 2 below. In dealing with business functions and support functions of the full set, multiple databases, is essential to a specific database therefore likely only to support functions (as shown in Figure 2> provide a subset of support. In order to reduce data redundancy and to make data more meaningful, has a complete, high-level business view is very helpful.The use of specific enterprise data model to describe the symbol. Apart from the graphical description of this type of entity, a complete enterprise data model should also include a description of each entity type description of business operations and a summary of that business rules. Business rules determine the validity of the data.An enterprise data model includes not only the types of entities, including the link between the data entities, as well as various other objects planning links. Showed that the linkage between planning targets a common form of matrix. Because of planning matrix need not be explicitmodeling database can be clearly described business needs, planning matrix is an important function. Regular planning matrix derived from the operational rules, it will help social development activities that top priority will be sorting and development activities under the top-down view through an enterprise-wide approach for the development of these activities. There are many types of planning matrix is available, their commonalities are:●locations - features show business function in which the implementation of operational locations.●unit - functions which showed that business function or business unit responsible for implementation.● Information System - data entities to explain how each information system interact with each data entity (for example, whether or not each system in each entity have the data to create, retrieve, update and delete>.● support functions - data in each functional entities in the data set for the acquisition, use, update and delete.●Information System - target indication for each information system to support business objectives.Figure 3 illustrate a possible functions - data entities matrix. Such a matrix can be used for a variety of purposes, including the following three objectives:1> identify gaps in the data entities to indicate the types of entities not use any function or functions which do not use any entity.2> found that the loss of each functional entities involved in the inspection staff through the matrix to identify any possible loss of the entity.3> The distinction between development activities if the priority to the top of a system development function for a high-priority (probably because it important organizational objectives related>, then this area used by entities in the development of the database has a high priority. Hoffer, George and Valacich (2002> are the works of the matrix on how to use the planning and completion of the Information EngineeringThe planning system more complete description.2 database development processBased on information engineering information systems planning database is a source of development projects. These new database development projects is usually in order to meet the strategic needs of organizations, such as improving customer support, improve product and inventory management, or a more accurate sales forecast. However, many more database development project is the bottom-up approach emerging, such as information system user needs specific information to complete their work, thus beginning a project request, and as other information systems experts found that organizations need to improve data management and begin new projects. Bottom-up even in the circumstances, to set up an enterprise data model is also necessary to understand the existing database can provide the necessary data, otherwise, the new database, data entities and attributes can be added to the current data resources to the organization. Both the strategic needs or operational information needs of each database development projects normally concentrated in a database. Some projects only concentrated in the database definition, design and implementation of a database, as a follow-up to the basis of the development of information systems. However, in most cases, the database and associated information processing function as a complete information systems development project was part of the development.2.1 System Development Life CycleGuide management information system development projects is the traditional process of system development life cycle (SDLC>. System development life cycle is an organization of the database designers and programmers information system composed of the Panel of Experts detailed description, development, maintenance and replacement of the entire information system steps. This process is because Waterfall than for every step into the adjacent the next step, that is, the information system is a specification developed by a piece of land, every piece of the output is under an input. However shown in the figure, these steps are not purely linear, each of the steps overlap in time (and thus can manage parallel steps>, but when the need to reconsider previous decisions, but also to roll back some steps ahead. (And therefore water can be put back in the waterfall!>Figure 4 on the system development life cycle and the purpose of each stage of the product can be delivered concise notes. The system development life cycle including each stage and database development-related activities, therefore, the question of database management systems throughout the entire development process. In Figure 5 we repeat of the system development life cycle stage of the seven, and outlines the common database at each stage of development activities. Please note that the systems development life cycle stages and database development steps一一对应exists between the relationship between the concept of modeling data in both systems development life cycle stages between.Enterprise ModelingDatabase development process from the enterprise modeling (system development life cycle stage of the project feasibility studies, and to choose a part>, Organizations set the scope and general database content. Enterprise modeling in information systems planning and other activities, these activities determine which part of information systems need to change and strengthen the entire organization and outlines the scope of data. In this step, check the current database and information systems, development of the project as the main areas of the nature of the business, with a very general description of each term in the development of information systems when needed data. Each item only when it achieved the expected goals of organizations can be when the next step.Conceptual Data ModelingOne has already begun on the Information System project, the concept of data modeling phase of the information systems needs of all the data. It is divided into two stages. First, it began the project in the planning stage and the establishment of a plan similar to Figure 1. At the same time outlining the establishment of other documents to the existing database without considering the circumstances specific development projects in the scope of the required data. This category only includes high-level data (entities>, and main contact. Then in the system development life-cycle analysis stage must have a management information system set the entire organization Details of the data model definition of all data attributes, listing all data types that all data inter-entity business linkages, defining description of the full data integrity rules. In the analysis phase, but also the concept of inspection data model (also called the concept behind the model> and the goal of information systems used to explain other aspects of the model of consistency categories, such as processing steps, rules and data processing time of timing. However, even if the concept is such detailed data model is only preliminary, because follow-up information system life cycle activities in the design of services, statements, display and inquiries may find that missing element or mistakes. Therefore, the concept of data often said that modeling is a top-down manner, its areas of operation from the general understanding of the driver, rather than the specific information processing activities by the driver.3. Logical Database DesignLogical database design from two perspectives database development. First, the concept of data model transform into relational database theory based on the criteria that means - between. Then, as the design of information systems, every computer procedures (including procedures for the input and output format>, database support services, statements, and inquiries revealed that a detailed examination. In this so-called Bottom-up analysis, accurate verification of the need to maintain the database and the data in each affairs, statements and so on the needs of those in the nature of the data.For each separate statements, services, and so on the analysis must take into account a specific, limited but complete database view. When statements, services, and other analysis might be necessary to change the concept of data model. Especially in large-scale projects, the different analytical systems development staff and the team can work independently in different procedures or in a centralized, the details of their work until all the logic design stage may be displayed. In these circumstances, logic database design stage must be the original concept of data model and user view these independent or merged into a comprehensive design. In logic design information systems also identify additional information processing needs of these new demands at this time must be integrated into the logic of earlier identified in the database design.Logical database design is based on the final step for the formation of good data specifications and determine the rules, the combination, the data after consultation specifications or converted into basic atomic element. Most of today's database, these rules from the relational database theory and the process known as standardization. This step is the result of management of these data have not cited any database management system for a complete description of the database map. Logical database design completed, we began to identify in detail the logic of the computer program and maintenance, the report contents of the database for inquiries.4. Physical database design and definitionPhysical database design and definition phase decisions computer memory (usually disk> database in the organization, definition ofAccording to the library management system for physical structure, the procedures outlined processing services, produce the desired management information and decision support statements. The objective of this stage is to design an effective and safe management of all data-processing database, the physical database design to closely integrate the information systems of other physical aspects of the design, including procedures, computer hardware, operating systems and data communications networks.5. Database ImplementationThe database prepared by the realization stage, testing and installation procedures for handling databases. Designers can use the standard programming language (such as COBOL, C or Visual Basic>, the dedicated database processing languages (such as SQL>, or the process of the non-exclusive language programming in order to produce a statement of the fixed format, the result will be displayed, and may also include charts. In achieving stage, but also the completion of all the database files, training users for information systems (database> user setup program. The final step is to use existing sources of information (documents legacy applications and databases and now needs new data> loading data. Loading data is often the first step in data from existing files and databases to an intermediate format (such as binary or text files> and then to turn intermediate loading data to a new database. Finally, running databases and related applications for the actual user maintenance and retrieval of data. In operation, the regular backup database and the database when damaged or affected resume database.6. Database maintenanceDuring the database in the progressive development of database maintenance. In this step, in order to meet changing business conditions, in order to correct the erroneous database design, database applications or processing speed increase, delete or change the structure of the database. When a procedure or failure of the computer database affect or damage the database may also be reconstruction. This step usually is the longest in the database development process step, as it continued to databases and related applications throughout the life cycle, the development of each database can be seen as a brief database development process and data modeling concepts arise, logical and physical database design and database to achieve dealing with the changes.2.2 Information System developed by other meansSystem Development Life Cycle minor changes in law or its variant of the often used to guide information systems and database development. Information System is a life-cycle methodology, it is highly structured approach, which includes many checks and balances to ensure that every step of produce accurate results, and new or alternative information system and it must communications or data definitions consistent existing system needs consistency. System development life cycle because of the regular need to have a working system for a long time been criticized because only work in the system until the end of the whole process generated. More and more organizations now use rapid application development method, it is a includes analysis, design and implementation of steps to repeat the rapid iterative process until convergence to users the system so far. Rapid Application Development Act required the database has been in existence, and enhance system is mainly to the application of data retrieval application, but not to those who generate and modify database applications.The most widely used method of rapid application development is one of the prototype. The prototype system is a method of iterative development process, analysts and users through close co-operation, continuing to revise the system will eventually convert all the needs of a working system. Figure 6 shows prototype of the process. In this diagram we contains notes, briefly describes each stage of the prototype of the database development activities. Normally, when information systems problems were identified, tried only a rough concept of data modeling. In the development of the initial prototype, the design of the user wants to display and statements, and that any new database needs and define a term prototype database. This is usually a new database, copy the part of the existing system, but might also added some new content. When the need for new content, these elements are usually from external data sources, such as market research data, the general economic indicators or industry standards.When a prototype of a new version to repeat the achievement and maintenance of database activities. Usually only a minimum level of security and integrity control, because at this time the focus is as soon as possible to produce a prototype version can be used. But document management project also deferred to the final, only be used in the delivery of user training. Finally, once constructed an acceptable prototype, developers, and users will be the final decision of whether to prototype delivery and the use of the database. If the system (including database> efficiency is very low, then the system and database will be re-programming and re-organization in order to achieve the desired performance.Along with visual programming tools (such as Visual Basic, Java, Visual C + + and fourth generation language> increasingly popular use of visual programming tools can easily change the user interface with the system, the prototype is becoming the choice of system development methodology. Customers using the prototype method statements and show changes to the content and layout is quite easy. In the process, the new database needs were identified, so it is the development of the use of the existing database should be amended. There is even the possibilityof a need for a new database system prototype method, in such circumstances, when the system demand in the iterative process of development in the ever-changing needs access to sample data, the construction or reconstruction of the database prototype.3 database development of the three-tier architecture modelIn this article on the front of the database development process mentioned in the interpretation of a system development project on the establishment of the several different, but related database view or model:● conceptual model (in the analysis stage of the establishment>.● external model or user view (in the analysis phase and the establishment of logical design phase>.● physical model or internal model (in the physical design phase of the establishment>. Figure 7 describes the database view that the relationship between the three, it is important to remember that they are the same organizations database view or model. In other words, each organization has a database of the physical model, a concept model and one or more users view. Therefore, the three-tier architecture model using the same data set observe the different ways definition database.Concept models on the full database structure, has nothing to do with the technical specifications. Conceptual model definition do not involve the entire database data stored in the computer how the secondary memory. Usually, the conceptual model by entities - links (E-R> map or object modeling symbols such a graphical format to describe, we have this type of concept model called the data model. In addition, the conceptual model specification as a metadata stored in the database or data dictionary.Physical models including conceptual model of how data stored in computer memory in the two specifications. Analysts and the database design is as important to the physical database (physical mode> definition, it provides information on the distribution and management of data storage and access of the physical memory space of two full database technology specifications.Database development and database technology database is among the three models divided into basis. Database development projects may have a role to only deal with these three views of a related work. For example, a beginner may be designed for one or more procedures external model, and an experienced developer will design the physical model or conceptual model. Database design issues at different levels are quite different.4 three-tier structure of the database positioning systemObviously, all the good things in the database are, and the "three"!When designing a database, you have to choose where to store data. This option in the physical database design stage. Database is divided into individual databases, the Working Group database, departmental databases, corporate databases and the Internet database. Individuals often by the end-user database design and development of their own, just by database experts to give training and advice to help, it only contains individual end-users interested in the data. Sometimes, personal database from the database or enterprise Working Group extracted from the database, such circumstances database prepared by some experts from the regular routine to create local database. Sector Working Group database and the database is often the end-user, business experts and the central database system experts development. The collaborative work of these officers is necessary because in the design of the database to be shared by a large number of issues weigh: processing speed, ease of use, data definition differences and other similar problems. Due to corporate databases and the Internet database broad impact, large-scale, it is normally concentrated in the database development team has received professional training to develop adatabase of experts.1. Customers layerA desktop or notebook also known as that layer, which specialized management user interface and system localization data in this layer can be implemented on the Web scripting tasks.2. Server / Web serverHTTP protocol handling, scripting tasks, the implementation of computing and provide data access, the layer known as processing services layer.3. Enterprise Server (Minicomputer or mainframe> layerThe implementation of complex computing and inter-organizational management from multiple data sources of data integration, also known as data services layer.In an organization, hierarchical database and information system architecture for distributed computing and the client / server architecture of the concept of correlation. Client / server architecture based on a LAN environment, including servers (referred to as database server or database engine> database software implementation from the client workstation database orders, each customer applications focus on their user interface functions. In fact, the whole concept of the database (as well as the application of these databases to handle routine> as a distributed database or the separate but related physical database distribution in the local PC workstation, server intermediate (working group or sector> and one center server (departments or enterprises >. Simply said that the use of client / server architecture for:●it can handle multiple processors on the same application at the same time, improve application response time and data processing speed.●It can use each computer platform of the best data processing (such as PC Minicom Advanced user interface with the mainframe and computing speed>.●can mix various client technology (Intel or Motorola processor assembly of personal computers, computer networks, information kiosks, etc.> and public data sharing. In addition, you can change the technology at any layer and other layers only a small influence on the system module.● able to handle close to the data source to be addressed to improve response time and reduce network traffic.● accept it to allow and encourage open systems standards.For database development, the use of a multi-layered client / server database architecture development is the most meaningful of the database will be easy to develop and maintain database module to the end-user and that the contents of the database information system module separated. That routine can be used as PowerBuilder, Java, and Visual Basic language to provide this easy-to-use graphical user interface. Through middleware that routine interaction between layers can be passed to access routine, the routine visit to the necessary data and analysis of these data in order to form the required information. As a database developers and programmers, you can in this three-tier level of any of the work, developing the necessary software.申明：所有资料为本人收集整理，仅限个人学习使用，勿做商业用途。
信息系统和数据库开发中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)Information System Development and DatabaseDevelopmentIn many organizations, database development from the beginning of enterprise data modeling, data modeling enterprises determine the scope of the database and the general content. This step usually occurs in an organization's information system planning process, it aims to help organizations create an overall data description or explanation, and not the design of a specific database. A specific database for one or more information systems provide data and the corporate data model (which may involve a number of databases) described by the organization maintaining the scope of the data. Data modeling in the enterprise, you review of the current system, the need to support analysis of the nature of the business areas, the need for further description of the abstract data, and planning one or more database developmentproject. Figure 1 shows Pine Valley furniture company's enterprise data model of a part.1.1 Information System ArchitectureSenior data model is only general information system architecture (ISA) or a part of an organization's information system blueprint. In the information system planning, you can build an enterprise data model as a whole information system architecture part. According to Zachman (1987), Sowa and Zachman (1992) views of an information system architecture consists of the following six key components:DataManipulation of data processing (of a data flow diagram can be used, with the object model methods, or other symbols that).Networks, which organizations and in organizations with its main transmission of data between business partners (it can connect through the network topology map and to demonstrate).People who deal with the implementation of data and information and is the source and receiver (in the process model for the data shows that the sender and the receiver).Implementation of the events and time points (they can use state transition diagram and other means.)The reasons for the incident and data processing rules (often in the form of text display, but there are also a number of charts for the planning tools such as decision tables).1.2 Information EngineeringInformation systems planners in accordance with the specific information system planning methods developed information system architecture. Information engineering is a popular and formal methods. Information engineering is a data-oriented creation and maintenance of the information system. Information engineering is because the data-oriented, so when you begin to understand how the database is defined by the logo and when information engineering a concise explanation is very helpful. Information Engineering follow top-down planning approach, in which specific information systems from a wide range of informationneeds in the understanding derived from (for example, we need about customers, products, suppliers, sales and processing of the data center), rather than merging many detailed information requested ( orders such as a screen or in accordance with the importation of geographical sales summary report). Top-down planning will enable developers to plan more comprehensive information system, consider system components provide an integrated approach to enhance the information system and the relationship between the business objectives of the understanding, deepen their understanding of information systems throughout the organization in understanding the impact.Information Engineering includes four steps: planning, analysis, design and implementation. The planning stage of project information generated information system architecture, including enterprise data model.1.3 Information System PlanningInformation systems planning objective is to enable IT organizations and the business strategy closely integrated, such integration for the information systems and technology to make the most of the investment interest is very important. As the table as a description, information engineering approach the planning stage include three steps, we in the follow-up of three sections they discussed.1. Critical factors determining the planningPlanning is the key factor that organizational objectives, critical success factors and problem areas. These factors determine the purpose of the establishment of planning and environment planning and information systems linked to strategic business planning. Table 2 shows the Pine Valley furniture company's key planning a number of possible factors, these factors contribute to the information systems manager for the new information systems and databases clubs top priority to deal with the demand. For example, given the imprecise sales forecasts this problem areas, information systems managers in the organization may be stored in the database additional historical sales data, new market research data and new product test data.2. The planning organizations set targetsOrganizations planning targets defined scope of business, and business scope will limit the subsequent analysis and information systems may change places. Five key planning targets as follows:● organizational units in the various sectors.● organizations location of the place of business operations.● functions of the business support organizations handling mission of the relevant group. Unlike business organizations function modules, in fact a function can be assigned to various organizations modules (for example, product development function is the production and sale of the common responsibility of the Ministry).● types of entities managed by the organization on the people, places and things of the major types of data.● Information System data set processing software applications and support procedures.3. To set up a business modelA comprehensive business model including the functions of each enterprise functional decomposition model, the enterprise data model and the various planning matrix. Functional decomposition is the function of the organization for a more detailed decomposition process, the functional decomposition is to simplify the analysis of the issue, distracted and identify components and the use of the classical approach. Pine Valley furniture company in order to function in the functional decomposition example in figure 2 below. In dealing with business functions and support functions of the full set, multiple databases, is essential to a specific database therefore likely only to support functions (as shown in Figure 2) provide a subset of support. In order to reduce data redundancy and to make data more meaningful, has a complete, high-level business view is very helpful.The use of specific enterprise data model to describe the symbol. Apart from the graphical description of this type of entity, a complete enterprise data model should also include a description of each entity type description of business operations and a summary of that business rules. Business rules determine the validity of the data.An enterprise data model includes not only the types of entities, including the link between the data entities, as well as various other objects planning links. Showed that the linkage between planning targets a common form of matrix. Because of planning matrix need not be explicit modeling database can be clearly described business needs, planning matrix is an important function. Regular planning matrix derived from theoperational rules, it will help social development activities that top priority will be sorting and development activities under the top-down view through an enterprise-wide approach for the development of these activities. There are many types of planning matrix is available, their commonalities are:● locations - features show business function in which the implementation of operational locations.● unit - functions which showed that business function or business unit responsible for implementation.● Information System - data entities to explain how each information system interact with each data entity (for example, whether or not each system in each entity have the data to create, retrieve, update and delete).● support functions - data in each functional entities in the data set for the acquisition, use, update and delete.● Information System - target indication for each information system to support business objectives.Data entities matrix. Such a matrix can be used for a variety of purposes, including the following three objectives:1) identify gaps in the data entities to indicate the types of entities not use any function or functions which do not use any entity.2) found that the loss of each functional entities involved in the inspection staff through the matrix to identify any possible loss of the entity.3) The distinction between development activities if the priority to the top of a system development function for a high-priority (probably because it important organizational objectives related), then this area used by entities in the development of the database has a high priority. Hoffer, George and Valacich (2002) are the works of the matrix on how to use the planning and completion of the Information Engineering.The planning system more complete description.2 database development processBased on information engineering information systems planning database is a source of development projects. These new database development projects is usuallyin order to meet the strategic needs of organizations, such as improving customer support, improve product and inventory management, or a more accurate sales forecast. However, many more database development project is the bottom-up approach emerging, such as information system user needs specific information to complete their work, thus beginning a project request, and as other information systems experts found that organizations need to improve data management and begin new projects. Bottom-up even in the circumstances, to set up an enterprise data model is also necessary to understand the existing database can provide the necessary data, otherwise, the new database, data entities and attributes can be added to the current data resources to the organization. Both the strategic needs or operational information needs of each database development projects normally concentrated in a database. Some projects only concentrated in the database definition, design and implementation of a database, as a follow-up to the basis of the development of information systems. However, in most cases, the database and associated information processing function as a complete information systems development project was part of the development.2.1 System Development Life CycleGuide management information system development projects is the traditional process of system development life cycle (SDLC). System development life cycle is an organization of the database designers and programmers information system composed of the Panel of Experts detailed description, development, maintenance and replacement of the entire information system steps. This process is because Waterfall than for every step into the adjacent the next step, that is, the information system is a specification developed by a piece of land, every piece of the output is under an input. However shown in the figure, these steps are not purely linear, each of the steps overlap in time (and thus can manage parallel steps), but when the need to reconsider previous decisions, but also to roll back some steps ahead. (And therefore water can be put back in the waterfall!)Figure 4 on the system development life cycle and the purpose of each stage of the product can be delivered concise notes. The system development life cycle including each stage and database development-related activities, therefore, the question of database management systems throughout the entire development process. In Figure 5 we repeat of the system development life cycle stage of the seven, and outlines thecommon database at each stage of development activities. Please note that the systems development life cycle stages and database development steps一一对应exists between the relationship between the concept of modeling data in both systems development life cycle stages between.Enterprise ModelingDatabase development process from the enterprise modeling (system development life cycle stage of the project feasibility studies, and to choose a part), Organizations set the scope and general database content. Enterprise modeling in information systems planning and other activities, these activities determine which part of information systems need to change and strengthen the entire organization and outlines the scope of data. In this step, check the current database and information systems, development of the project as the main areas of the nature of the business, with a very general description of each term in the development of information systems when needed data. Each item only when it achieved the expected goals of organizations can be when the next step.Conceptual Data ModelingOne has already begun on the Information System project, the concept of data modeling phase of the information systems needs of all the data. It is divided into two stages. First, it began the project in the planning stage and the establishment of a plan similar to Figure 1. At the same time outlining the establishment of other documents to the existing database without considering the circumstances specific development projects in the scope of the required data. This category only includes high-level data (entities), and main contact. Then in the system development life-cycle analysis stage must have a management information system set the entire organization Details of the data model definition of all data attributes, listing all data types that all data inter-entity business linkages, defining description of the full data integrity rules. In the analysis phase, but also the concept of inspection data model (also called the concept behind the model) and the goal of information systems used to explain other aspects of the model of consistency categories, such as processing steps, rules and data processing time of timing. However, even if the concept is such detailed data model is only preliminary, because follow-up information system life cycle activities in the design of services, statements, display and inquiries may find that missing element or mistakes. Therefore, the concept of data often said that modeling is atop-down manner, its areas of operation from the general understanding of the driver, rather than the specific information processing activities by the driver.3. Logical Database DesignLogical database design from two perspectives database development. First, the concept of data model transform into relational database theory based on the criteria that means - between. Then, as the design of information systems, every computer procedures (including procedures for the input and output format), database support services, statements, and inquiries revealed that a detailed examination. In this so-called Bottom-up analysis, accurate verification of the need to maintain the database and the data in each affairs, statements and so on the needs of those in the nature of the data.For each separate statements, services, and so on the analysis must take into account a specific, limited but complete database view. When statements, services, and other analysis might be necessary to change the concept of data model. Especially in large-scale projects, the different analytical systems development staff and the team can work independently in different procedures or in a centralized, the details of their work until all the logic design stage may be displayed. In these circumstances, logic database design stage must be the original concept of data model and user view these independent or merged into a comprehensive design. In logic design information systems also identify additional information processing needs of these new demands at this time must be integrated into the logic of earlier identified in the database design.Logical database design is based on the final step for the formation of good data specifications and determine the rules, the combination, the data after consultation specifications or converted into basic atomic element. Most of today's database, these rules from the relational database theory and the process known as standardization. This step is the result of management of these data have not cited any database management system for a complete description of the database map. Logical database design completed, we began to identify in detail the logic of the computer program and maintenance, the report contents of the database for inquiries.4. Physical database design and definitionPhysical database design and definition phase decisions computer memory (usuallydisk) database in the organization, definition of According to the library management system for physical structure, the procedures outlined processing services, produce the desired management information and decision support statements. The objective of this stage is to design an effective and safe management of all data-processing database, the physical database design to closely integrate the information systems of other physical aspects of the design, including procedures, computer hardware, operating systems and data communications networks.5. Database ImplementationThe database prepared by the realization stage, testing and installation procedures for handling databases. Designers can use the standard programming language (such as COBOL, C or Visual Basic), the dedicated database processing languages (such as SQL), or the process of the non-exclusive language programming in order to produce a statement of the fixed format, the result will be displayed, and may also include charts. In achieving stage, but also the completion of all the database files, training users for information systems (database) user setup program. The final step is to use existing sources of information (documents legacy applications and databases and now needs new data) loading data. Loading data is often the first step in data from existing files and databases to an intermediate format (such as binary or text files) and then to turn intermediate loading data to a new database. Finally, running databases and related applications for the actual user maintenance and retrieval of data. In operation, the regular backup database and the database when damaged or affected resume database.6. Database maintenanceDuring the database in the progressive development of database maintenance. In this step, in order to meet changing business conditions, in order to correct the erroneous database design, database applications or processing speed increase, delete or change the structure of the database. When a procedure or failure of the computer database affect or damage the database may also be reconstruction. This step usually is the longest in the database development process step, as it continued to databases and related applications throughout the life cycle, the development of each database can be seen as a brief database development process and data modeling concepts arise, logical and physical database design and database to achieve dealing with the changes.2.2 Information System developed by other meansSystem Development Life Cycle minor changes in law or its variant of the often used to guide information systems and database development. Information System is a life-cycle methodology, it is highly structured approach, which includes many checks and balances to ensure that every step of produce accurate results, and new or alternative information system and it must communications or data definitions consistent existing system needs consistency. System development life cycle because of the regular need to have a working system for a long time been criticized because only work in the system until the end of the whole process generated. More and more organizations now use rapid application development method, it is a includes analysis, design and implementation of steps to repeat the rapid iterative process until convergence to users the system so far. Rapid Application Development Act required the database has been in existence, and enhance system is mainly to the application of data retrieval application, but not to those who generate and modify database applications.The most widely used method of rapid application development is one of the prototype. The prototype system is a method of iterative development process, analysts and users through close co-operation, continuing to revise the system will eventually convert all the needs of a working system. Figure 6 shows prototype of the process. In this diagram we contains notes, briefly describes each stage of the prototype of the database development activities. Normally, when information systems problems were identified, tried only a rough concept of data modeling. In the development of the initial prototype, the design of the user wants to display and statements, and that any new database needs and define a term prototype database. This is usually a new database, copy the part of the existing system, but might also added some new content. When the need for new content, these elements are usually from external data sources, such as market research data, the general economic indicators or industry standards.When a prototype of a new version to repeat the achievement and maintenance of database activities. Usually only a minimum level of security and integrity control, because at this time the focus is as soon as possible to produce a prototype version can be used. But document management project also deferred to the final, only be used in the delivery of user training. Finally, once constructed an acceptable prototype,developers, and users will be the final decision of whether to prototype delivery and the use of the database. If the system (including database) efficiency is very low, then the system and database will be re-programming and re-organization in order to achieve the desired performance.Along with visual programming tools (such as Visual Basic, Java, Visual C + + and fourth generation language) increasingly popular use of visual programming tools can easily change the user interface with the system, the prototype is becoming the choice of system development methodology. Customers using the prototype method statements and show changes to the content and layout is quite easy. In the process, the new database needs were identified, so it is the development of the use of the existing database should be amended. There is even the possibility of a need for a new database system prototype method, in such circumstances, when the system demand in the iterative process of development in the ever-changing needs access to sample data, the construction or reconstruction of the database prototype.3 database development of the three-tier architecture modelIn this article on the front of the database development process mentioned in the interpretation of a system development project on the establishment of the several different, but related database view or model:● conceptual model (in the analysis stage of the establishment).● external model or user view (in the analysis phase and the establishment of logical design phase).● physical model or internal model (in the physical design phase of the establishment).Figure 7 describes the database view that the relationship between the three, it is important to remember that they are the same organizations database view or model. In other words, each organization has a database of the physical model, a concept model and one or more users view.Therefore, the three-tier architecture model using the same data set observe the different ways definition database.Concept models on the full database structure, has nothing to do with the technical specifications. Conceptual model definition do not involve the entire database datastored in the computer how the secondary memory. Usually, the conceptual model by entities - links (E-R) map or object modeling symbols such a graphical format to describe, we have this type of concept model called the data model. In addition, the conceptual model specification as a metadata stored in the database or data dictionary.Physical models including conceptual model of how data stored in computer memory in the two specifications. Analysts and the database design is as important to the physical database (physical mode) definition, it provides information on the distribution and management of data storage and access of the physical memory space of two full database technology specifications.Database development and database technology database is among the three models divided into basis. Database development projects may have a role to only deal with these three views of a related work. For example, a beginner may be designed for one or more procedures external model, and an experienced developer will design the physical model or conceptual model. Database design issues at different levels are quite different.4 three-tier structure of the database positioning systemObviously, all the good things in the database are, and the "three"!When designing a database, you have to choose where to store data. This option in the physical database design stage. Database is divided into individual databases, the Working Group database, departmental databases, corporate databases and the Internet database. Individuals often by the end-user database design and development of their own, just by database experts to give training and advice to help, it only contains individual end-users interested in the data. Sometimes, personal database from the database or enterprise Working Group extracted from the database, such circumstances database prepared by some experts from the regular routine to create local database. Sector Working Group database and the database is often the end-user, business experts and the central database system experts development. The collaborative work of these officers is necessary because in the design of the database to be shared by a large number of issues weigh: processing speed, ease of use, data definition differences and other similar problems. Due to corporate databases and the Internet database broad impact, large-scale, it is normally concentrated in the database development team has received professional training to develop a database of experts.1. Customers layerA desktop or notebook also known as that layer, which specialized management user interface and system localization data in this layer can be implemented on the Web scripting tasks.2. Server / Web serverHTTP protocol handling, scripting tasks, the implementation of computing and provide data access, the layer known as processing services layer.3. Enterprise Server (Minicomputer or mainframe) layerThe implementation of complex computing and inter-organizational management from multiple data sources of data integration, also known as data services layer.In an organization, hierarchical database and information system architecture for distributed computing and the client / server architecture of the concept of correlation. Client / server architecture based on a LAN environment, including servers (referred to as database server or database engine) database software implementation from the client workstation database orders, each customer applications focus on their user interface functions. In fact, the whole concept of the database (as well as the application of these databases to handle routine) as a distributed database or the separate but related physical database distribution in the local PC workstation, server intermediate (working group or sector) and one center server (departments or enterprises ). Simply said that the use of client / server architecture for:● it can handle multiple processors on the same application at the same time, improve application response time and data processing speed.● It can use each computer platform of the best data processing (such as PC Minicom Advanced user interface with the mainframe and computing speed).● can mix various client technology (Intel or Motorola processor assembly of personal computers, computer networks, information kiosks, etc.) and public data sharing. In addition, you can change the technology at any layer and other layers only a small influence on the system module.● able to handle close to the data source to be addressed to improve response time and reduce network traffic.。
数据库管理系统毕业论文中英文资料对照外文翻译文献综述
数据库管理系统毕业论文中英文资料对照外文翻译文献综述中英文资料对照外文翻译文献综述英文翻译数据库管理系统的介绍Raghu Ramakrishnan数据库（database,有时被拼作data base）又称为电子数据库，是专门组织起来的一组数据或信息，其目的是为了便于计算机快速查询及检索。
数据库的结构是专门设计的，在各种数据处理操作命令的支持下，可以简化数据的存储、检索、修改和删除。
数据库可以存储在磁盘、磁带、光盘或其他辅助存储设备上。
数据库由一个或一套文件组成，其中的信息可以分解为记录，每一条记录又包含一个或多个字段（或称为域）。
字段是数据存取的基本单位。
数据库用于描述实体，其中的一个字段通常表示与实体的某一属性相关的信息。
通过关键字以及各种分类（排序）命令，用户可以对多条记录的字段进行查询，重新整理，分组或选择，以实体对某一类数据的检索，也可以生成报表。
所有数据库（除最简单的）中都有复杂的数据关系及其链接。
处理与创建，访问以及维护数据库记录有关的复杂任务的系统软件包叫做数据库管理系统（DBMS）。
DBMS软件包中的程序在数据库与其用户间建立接口。
（这些用户可以是应用程序员，管理员及其他需要信息的人员和各种操作系统程序）DBMS可组织、处理和表示从数据库中选出的数据元。
该功能使决策者能搜索、探查和查询数据库的内容，从而对正规报告中没有的，不再出现的且无法预料的问题做出回答。
这些问题最初可能是模糊的并且（或者）是定义不恰当的，但是人们可以浏览数据库直到获得所需的信息。
简言之，DBMS将“管理”存储的数据项和从公共数据库中汇集所需的数据项用以回答非程序员的询问。
DBMS由3个主要部分组成：（1）存储子系统，用来存储和检索文件中的数据；（2）建模和操作子系统，提供组织数据以及添加、删除、维护、更新数据的方法；（3）用户和DBMS之间的接口。
在提高数据库管理系统的价值和有效性方面正在展现以下一些重要发展趋势：1.管理人员需要最新的信息以做出有效的决策。
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中英文对照翻译信息系统开发和数据库开发在许多组织中，数据库开发是从企业数据建模开始的，企业数据建模确定了组织数据库的范围和一般内容。
这一步骤通常发生在一个组织进行信息系统规划的过程中，它的目的是为组织数据创建一个整体的描述或解释，而不是设计一个特定的数据库。
一个特定的数据库为一个或多个信息系统提供数据，而企业数据模型（可能包含许多数据库）描述了由组织维护的数据的范围。
在企业数据建模时，你审查当前的系统，分析需要支持的业务领域的本质，描述需要进一步抽象的数据，并且规划一个或多个数据库开发项目。
图1显示松谷家具公司的企业数据模型的一个部分。
1.1 信息系统体系结构如图1所示，高级的数据模型仅仅是总体信息系统体系结构(ISA)一个部分或一个组织信息系统的蓝图。
在信息系统规划期间，你可以建立一个企业数据模型作为整个信息系统体系结构的一部分。
根据Zachman(1987)、Sowa和Zachman （1992）的观点，一个信息系统体系结构由以下6个关键部分组成: 数据（如图1所示，但是也有其他的表示方法）。
操纵数据的处理（着系可以用数据流图、带方法的对象模型或者其他符号表示）。
网络，它在组织内并在组织与它的主要业务伙伴之间传输数据（它可以通过网络连接和拓扑图来显示）。
人，人执行处理并且是数据和信息的来源和接收者（人在过程模型中显示为数据的发送者和接收者）。
执行过程的事件和时间点（它们可以用状态转换图和其他的方式来显示）。
事件的原因和数据处理的规则（经常以文本形式显示，但是也存在一些用于规划的图表工具，如决策表）。
1.2 信息工程信息系统的规划者按照信息系统规划的特定方法开发出信息系统的体系结构。
信息工程是一种正式的和流行的方法。
信息工程是一种面向数据的创建和维护信息系统的方法。
因为信息工程是面向数据的，所以当你开始理解数据库是怎样被标识和定义时，信息工程的一种简洁的解释是非常有帮助的。
信息工程遵循自顶向下规划的方法，其中，特定的信息系统从对信息需求的广泛理解中推导出来（例如，我们需要关于顾客、产品、供应商、销售员和加工中心的数据），而不是合并许多详尽的信息请求（如一个订单输入屏幕或按照地域报告的销售汇总）。
自顶向下规划可使开发人员更全面地规划信息系统，提供一种考虑系统组件集成的方法，增进对信息系统与业务目标的关系的理解，加深对信息系统在整个组织中的影响的理解。
信息工程包括四个步骤:规划、分析、设计和实现。
信息工程的规划阶段产生信息系统体系结构，包括企业数据模型。
1.3 信息系统规划信息系统规划的目标是使信息技术与组织的业务策略紧密结合，这种结合对于从信息系统和技术的投资中获取最大利益是非常重要的。
正如表1所描述的那样，信息工程方法的规划阶段包括3个步骤，我们在后续的3个小节中讨论它们。
1.确定关键性的规划因素关键性的规划因素是指组织目标、关键的成功因素和问题领域。
确定这些因素的目的是建立规划的环境并且将信息系统规划与战略业务规划联系起来。
表2显示了松谷家具公司的一些可能的关键规划因素，这些因素有助于信息系统的管理者为新的信息系统和数据库社顶优先级以处理需求。
例如，考虑到不精确的销售预测这个问题领域，信息系统的管理者可能在组织数据库中存放额外的历史销售数据、新的市场研究数据和新产品的测试数据。
2.确定组织的规划对象组织规划对象定义了业务范围，业务范围会限制后来的系统分析和信息系统可能发生改变的地方。
五个关键的规划对象如下所示:●组织单元组织中的各种部门。
●组织地点业务操作的发生地。
●业务功能支持组织使命的业务处理的相关组。
业务功能不同于组织单元，事实上一个功能可以分配给多个组织单元（例如，产品开发功能可能是销售部和生产部共同的责任）。
●实体类型关于组织所管理的人，地点和事物的数据的主要类别。
●信息系统处理数据集的应用软件和支持程序。
3.建立企业模型一个全面的企业模型包括每个企业功能的功能分解模型、企业数据模型和各种规划矩阵。
功能分解是把组织的功能进行更详细的分解过程，功能分解是在系统分析中为了简化问题、分散注意力和确定组件而使用的经典处理方法。
在松谷家具公司中订单履行功能的功能分解的例子如图2所示。
对于处理业务功能和支持功能的全部集合而言，多个数据库是必须的，因此一个特定的数据库可能仅仅对支持功能（如图2所示）的一个子集提供支持。
为了减少数据冗余和使数据更有意义，拥有完整的、高层次的企业视图是非常有帮助的。
企业数据模型使用特定的符号来描述。
除了实体类型这种图形描述外，一个完整的企业数据模型还应包括每个实体类型的描述和描述业务操作的提要，即业务规则。
业务规则决定数据的有效性。
一个企业数据模型不仅包括实体类型，还包括数据实体间的联系，以及各种规划对象间的其他联系。
显示规划对象间联系的一种常见形式是矩阵。
由于规划矩阵不需要数据库被明确的建模就可以明确描述业务需求，因此规划矩阵是一种重要的功能。
规划矩阵经常从业务规则中导出，它有助于社顶开发活动优先级、将开发活动排序和根据自顶向下视图通过一种企业范围的方法安排这些开发活动。
有许多种规划矩阵可供使用，它们的共同之处是:●地点-功能显示业务功能在哪个业务地点执行。
●单元-功能显示业务功能由哪个业务单元执行或负责。
●信息系统-数据实体解释每个信息系统如何与每个数据实体相互作用（例如，是否每个系统都对每个实体中的数据进行创建、检索、更新和删除）。
●支持功能-数据实体确定每个功能中数据的获取、使用、更新和删除。
●信息系统-目标显示信息系统支持的每个业务目标图3举例说明了一个可能的功能-数据实体矩阵。
这样的矩阵可以用于多种目的，包括以下三个目的:1)确定空白实体显示哪些数据实体没有被任何功能使用或哪个功能没有使用任何实体。
2)发现丢失的实体每个功能涉及的员工通过检查矩阵能够确认任何可能丢失的实体。
3)区分开发活动的优先级如果一个给顶的功能对于系统开发有高优先级（可能因为它与重要的组织目标相关），那么这个领域所使用的实体在数据库开发中拥有高优先级。
Hoffer、George和Valacich(2002)的著作中有关于怎样使用规划矩阵完成信息工程和系统规划的更完整的描述。
2数据库开发过程基于信息工程的信息系统规划是数据库开发项目的一个来源。
这些开发新数据库的项目通常是为了满足组织的战略需求，例如改善客户支持、提高产品和库存管理或进行更精确的销售预测。
然而许多数据库开发项目更多的是以自底向上的方式出现的，例如信息系统的用户需要特定的信息来完成他们的工作，从而请求开始一个项目，又如其他信息系统的专家发现组织需要改进数据管理而开始新的项目。
即使在自底向上的情况下，建立企业数据模型也是必须的，以便理解现有的数据库是否可以提供所需的数据，否则，新的数据库、数据实体和属性都应该加到当前的组织数据资源中去。
无论是战略需求还是操作信息的需求，每个数据库开发项目通常集中在一个数据库上。
一些数据库项目仅仅集中在定义、设计和实现一个数据库，以作为后续信息系统开发的基础。
然而在大多数情况下，数据库及其相关信息处理功能是作为一个完整的信息系统开发项目的一部分而被开发的。
2.1 系统开发生命周期指导管理信息系统开发项目的传统过程是系统开发生命周期(SDLC)。
系统开发生命周期是指一个组织中由数据库设计人员和程序员组成的信息系统专家小组详细说明、开发、维护和替换信息系统的全部步骤。
这个过程比作瀑布是因为每一步都流到相邻的下一步，即信息系统的规格说明是一块一块地开发出来的，每一块的输出是下一块的输入。
然而如图所示，这些步骤并不是纯线性的，每个步骤在时间上有所重叠（因此可以并行地管理步骤），而且当需要重新考虑先前的决策时，还可以回滚到前面某些步骤。
（因而水可以在瀑布中倒流！）图4对系统开发生命周期每一阶段的目的和可交付的产品进行了简明注解。
系统开发生命周期的每一阶段都包括与数据库开发相关的活动，所以，数据库管理的问题遍布整个系统开发过程。
我们在图5中重复了系统开发生命周期的七个阶段，并概述了每个阶段常见的数据库开发活动。
请注意，系统开发生命周期的阶段和数据库开发步骤之间不存在一一对应的关系，概念数据建模发生在两个系统开发生命周期阶段之间。
企业建模数据库开发过程从企业建模（系统开发生命周期中项目论证和选择阶段的一部分）开始设定组织数据库的范围和一般内容。
企业建模发生在信息系统规划和其他活动期间，这些活动确定信息系统的哪个部分需要改变和加强并概述出全部组织数据的范围。
在这一步中，检查当前数据库和信息系统，分析作为开发项目主体的业务领域的本质，用非常一般的术语描述每个信息系统在开发时所需要的数据。
每个项目只有当它达到组织的预期目标时才可以进行下一步。
概念数据建模对一个已经开始的信息系统项目而言，概念数据建模阶段分析信息系统的全部数据需求。
它分为两个阶段。
首先，它在项目开始和规划阶段建立一张类似于图1的图。
同时建立其他文档来概述不考虑现存数据库的情况下特定开发项目中所需的数据范围。
此时仅仅包括高层类别的数据（实体）和主要联系。
然后在系统开发生命周期的分析阶段产生确定信息系统必须管理的全部组织数据的详细数据模型，定义所有数据属性，列出全部数据类别，表示数据实体间所有的业务联系，确定描述数据完整性的全部规则。
在分析阶段，还要检查概念数据模型（在后面也称作概念模式）与用来解释目标信息系统其他方面的模型类别的一致性，例如处理步骤、处理数据的规则以及时间的时序。
然而，即使是这样详细的概念数据模型也只是初步的，因为后续的信息系统生命周期中的活动在设计事务、报表、显示和查询时可能会发现遗漏的元素或错误。
因此，经常说到的概念数据建模是以一种自顶向下的方式完成的，它由业务领域的一般理解所驱动，而不是由特定的信息处理活动所驱动。
3.逻辑数据库设计逻辑数据库设计从两个角度进行数据库开发。
首先，将概念数据模型变换成基于关系数据库理论的标准表示方法——关系。
然后像设计信息系统的每个计算机程序（包括程序的输入和输出格式）那样，对数据库支持的事务、报表、显示和查询进行详细的检查。
在这个所谓的自底向上的分析中，精确地验证数据库中需要维护的数据和在每个事务、报表等等中需要的那些数据的性质。
对于每个单独的报表、事务等等的分析都要考虑一个特定的、有限制的但是完全的数据库视图。
当报表、事务等被分析时有可能根据需要而改变概念数据模型。
尤其在大型的项目中，不同的分析人员和系统开发者的团队可以独立地工作在不同的程序或程序集中，他们所有工作的细节直到逻辑设计阶段才可能会显示出来。
在这种情况下，逻辑数据库设计阶段必须将原始的概念数据模型和这些独立的用户视图合并或集成到一个全面的设计中。
在进行逻辑信息系统设计时也可以确定额外的信息处理需求，此时这些新的需求必须集成到前面确定的逻辑数据库设计中。