数据库的连接串大全
SQL server 和MySQL的 connectionstring大全
【SQL SERVER】Standard SecurityData Source=myServerAddress;Initial Catalog=myDataBase;UserId=myUsername;Password=myPassword;Standard Security alternative syntaxThis connection string produces the same result as the previous one. The reason to include it is to point out that some connection string keywords have many equivalents.Server=myServerAddress;Database=myDataBase;UserID=myUsername;Password=myPassword;Trusted_Connection=False;Trusted ConnectionData Source=myServerAddress;Initial Catalog=myDataBase;IntegratedSecurity=SSPI;Trusted Connection alternative syntaxThis connection string produce the same result as the previous one. The reason to include it is to point out that some connection string keywords have many equivalents.Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;Use serverName\instanceName as Data Source to use a specific SQL Server instance. Please note that the multiple SQL Server instances feature is available only from SQL Server version 2000 and not in any previous versions.Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Server=myServerName\theInstanceName;Database=myDataBase;Trusted_Connection=T rue;Trusted Connection from a CE deviceOften a Windows CE device is not authenticated and logged in to a domain. To use SSPI or trusted connection / authentication from a CE device, use this connection string.Data Source=myServerAddress;Initial Catalog=myDataBase;IntegratedSecurity=SSPI;User ID=myDomain\myUsername;Password=myPassword;Note that this will only work on a CE device.Read more about connecting to SQL Server from CE devices hereConnect via an IP addressData Source=190.190.200.100,1433;Network Library=DBMSSOCN;InitialCatalog=myDataBase;User ID=myUsername;Password=myPassword;Specifying packet sizeServer=myServerAddress;Database=myDataBase;UserID=myUsername;Password=myPassword;Trusted_Connection=False;Packet Size=4096; By default, the Microsoft .NET Framework Data Provider for SQL Server sets the network packet size to 8192 bytes. This might however not be optimal, try to set this value to 4096 instead.The default value of 8192 might cause errors as well ("Failed to reserve contiguous memory"), check this outMicrosoft OLE DB Provider for SQL Serv erType: OLE DB ProviderUsage:Provider=sqloledbManufacturer: MicrosoftMore info about this provider »Customize stringexample values »Standard SecurityProvider=sqloledb;Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;Trusted connectionProvider=sqloledb;Data Source=myServerAddress;InitialCatalog=myDataBase;Integrated Security=SSPI;Use serverName\instanceName as Data Source to use a specific SQL Server instance. Please note that the multiple SQL Server instances feature is available only from SQL Server version 2000 and not in any previous versions.Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Provider=sqloledb;Data Source=myServerName\theInstanceName;InitialCatalog=myDataBase;Integrated Security=SSPI;Prompt for username and passwordThis one is a bit tricky. First set the connection object's Provider property to "sqloledb". Thereafter set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Provider = "sqloledb"oConn.Properties("Prompt") = adPromptAlwaysData Source=myServerAddress;Initial Catalog=myDataBase;Connect via an IP addressProvider=sqloledb;Data Source=190.190.200.100,1433;NetworkLibrary=DBMSSOCN;Initial Catalog=myDataBase;UserID=myUsername;Password=myPassword;DBMSSOCN=TCP/IP. This is how to use TCP/IP instead of Named Pipes. At the end of the Data Source is the port to use. 1433 is the default port for SQL Server.How to define which network protocol to useDisable connection poolingThis one is usefull when receving errors "sp_setapprole was not invoked correctly." (7.0) or "General network error. Check your network documentation" (2000) when connecting using an application role enabled connection. Application pooling (or OLE DB resource pooling) is on by default. Disabling it can help on this error.Provider=sqloledb;Data Source=myServerAddress;Initial Catalog=myDataBase;User ID=myUsername;Password=myPassword;OLE DB Services=-2;.NET Framework Data Provider for OLE DBType: .NET Framework Wrapper Class LibraryUsage:System.Data.OleDb.OleDbConnectionManufacturer: MicrosoftMore info about this wrapper class library »Customize stringexample values »Bridging to OLE DB Provider for SQL ServerThis is just one connection string sample for the wrapping OleDbConnection class that calls the underlying OLEDB provider. See respective OLE DB provider for more connection strings to use with this class.Provider=SQLOLEDB;Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername; Password=myPassword;Microsoft SQL Server ODBC DriverType: ODBC DriverUsage:Driver={SQL Server}Manufacturer: MicrosoftCustomize stringexample values »Standard SecurityDriver={SQLServer};Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPass word;Trusted connectionDriver={SQLServer};Server=myServerAddress;Database=myDataBase;Trusted_Connection=Yes;Prompt for username and passwordThis one is a bit tricky. First you need to set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Properties("Prompt") = adPromptAlwaysDriver={SQL Server};Server=myServerAddress;Database=myDataBase;SQL Server Native Client 10.0 OLE DB ProviderType: OLE DB ProviderUsage:Provider=SQLNCLI10Manufacturer: MicrosoftMore info about this provider »Customize stringexample values »Standard securityNote that the SQL Server Native Client OLE DB Provider does not support SQL Server 7.0. Provider=SQLNCLI10;Server=myServerAddress;Database=myDataBase;Uid=myUsername; Pwd=myPassword;Trusted connectionProvider=SQLNCLI10;Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes;Equivalent key-value pair: "Integrated Security=SSPI" equals "Trusted_Connection=yes"Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Provider=SQLNCLI10;Server=myServerName\theInstanceName;Database=myDataBase; Trusted_Connection=yes;Prompt for username and passwordThis one is a bit tricky. First you need to set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Properties("Prompt") = adPromptAlwaysoConn.Open "Provider=SQLNCLI10;Server=myServerAddress;DataBase=myDataBase;Encrypt data sent over networkProvider=SQLNCLI10;Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes;Encrypt=yes;SQL Native Client 9.0 OLE DB providerType: OLE DB ProviderUsage:Provider=SQLNCLIManufacturer: MicrosoftMore info about this provider »Customize stringexample values »Standard securityNote that the SQL Server Native Client OLE DB Provider does not support SQL Server 7.0. Provider=SQLNCLI;Server=myServerAddress;Database=myDataBase;Uid=myUsername; Pwd=myPassword;Trusted connectionProvider=SQLNCLI;Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes;Equivalent key-value pair: "Integrated Security=SSPI" equals "Trusted_Connection=yes"Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Provider=SQLNCLI;Server=myServerName\theInstanceName;Database=myDataBase; Trusted_Connection=yes;Prompt for username and passwordThis one is a bit tricky. First you need to set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Properties("Prompt") = adPromptAlwaysoConn.Open "Provider=SQLNCLI;Server=myServerAddress;DataBase=myDataBase;Encrypt data sent over networkProvider=SQLNCLI;Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes;Encrypt=yes;SQL Server Native Client 10.0 ODBC DriverType: ODBC DriverUsage:Driver={SQL Server Native Client 10.0}Manufacturer: MicrosoftMore info about this driver »Customize stringexample values »Standard securityDriver={SQL Server Native Client10.0};Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPasswo rd;Trusted ConnectionDriver={SQL Server Native Client10.0};Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes; Equivalent key-value pair: "Integrated Security=SSPI" equals "Trusted_Connection=yes"Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Driver={SQL Server Native Client 10.0};Server=myServerName\theInstanceName; Database=myDataBase;Trusted_Connection=yes;Prompt for username and passwordThis one is a bit tricky. First you need to set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Properties("Prompt") = adPromptAlwaysDriver={SQL Server Native Client10.0};Server=myServerAddress;Database=myDataBase;Encrypt data sent over networkDriver={SQL Server Native Client10.0};Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes;Encrypt=yes;SQL Native Client 9.0 ODBC DriverType: ODBC DriverUsage:Driver={SQL Native Client}Manufacturer: MicrosoftMore info about this driver »Customize stringexample values »Standard securityDriver={SQL Native Client};Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Trusted ConnectionDriver={SQL Native Client};Server=myServerAddress;Database=myDataBase; Trusted_Connection=yes;Equivalent key-value pair: "Integrated Security=SSPI" equals "Trusted_Connection=yes"Connecting to an SQL Server instanceThe syntax of specifying the server instance in the value of the server key is the same for all connection strings for SQL Server.Driver={SQL NativeClient};Server=myServerName\theInstanceName;Database=myDataBase;Trusted_Connection=yes;Prompt for username and passwordThis one is a bit tricky. First you need to set the connection object's Prompt property to adPromptAlways. Then use the connection string to connect to the database.oConn.Properties("Prompt") = adPromptAlwaysDriver={SQL Native Client};Server=myServerAddress;Database=myDataBase;Customize stringexample values »MSDataShapeProvider=MSDataShape;Data Provider=SQLOLEDB;DataSource=myServerAddress;Initial Catalog=myDataBase;UserID=myUsername;Password=myPassword;【MYSQL】StandardServer=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword; Default port is 3306.Specifying portServer=myServerAddress;Port=1234;Database=myDataBase;Uid=myUsername;Pwd=myPa ssword;Download the driver at MySQL Developer ZoneNamed pipesServer=myServerAddress;Port=-1;Database=myDataBase;Uid=myUsername;Pwd=myPass word;It is the port value of -1 that tells the driver to use named pipes network protocol. This is available on Windows only. The value is ignored if Unix socket is used.Multiple serversUse this to connect to a server in a replicated server configuration without concern on which server to use.Server=serverAddress1 & serverAddress2 &etc..;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Using encryptionThis one activates SSL encryption for all data sent between the client and server. The server needs to have a certificate installed.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Enc ryption=true;This option is available from Connector/NET version 5.0.3. In earlier versions, this option has no effect.Using encryption, alternativeSome reported problems with the above one. Try replacing the key "Encryption" with "Encrypt" instead.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Enc rypt=true;Specifying default command timeoutUse this one to specify a default command timeout for the connection. Please note that the property in the connection string does not supercede the individual command timeout property on an individual command object.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;def ault command timeout=20;This option is available from Connector/NET version 5.1.4.Specifying connection attempt timeoutUse this one to specify the length in seconds to wait for a server connection before terminating the attempt and receive an error.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Con nection Timeout=5;Inactivating prepared statementsUse this one to instruct the provider to ignore any command prepare statements and prevent corruption issues with server side prepared statements.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Ign ore Prepare=true;The option was added in Connector/NET version 5.0.3 and Connector/NET version 1.0.9.Specifying portUse this one to specify what port to use for the connection.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;Por t=3306;The port 3306 is the default MySql port.The value is ignored if Unix socket is used.Specifying network protocolUse this one to specify which network protocol to use for the connection.Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword; Protocol=socket;"socket" is the default value used if the key isn't specified. Value "tcp" is an equivalent for "socket".Manufacturer: MySQLMore info about this driver »Customize stringexample values »Local databaseDriver={MySQL ODBC 3.51 Driver};Server=localhost;Database=myDataBase;User=myUsername;Password=myPassword;Option=3;Remote databaseDriver={MySQL ODBC 3.51Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;Option=3;Specifying TCP/IP portDriver={MySQL ODBC 3.51Driver};Server=myServerAddress;Port=3306;Database=myDataBase;User=myUsername; Password=myPassword;Option=3;The driver defaults to port value 3306, if not specified in the connection string, as 3306 is the default port for MySQL.Specifying character setDriver={MySQL ODBC 3.51Driver};Server=myServerAddress;charset=UTF8;Database=myDataBase;User=myUsern ame; Password=myPassword;Option=3;Note that the charset option works from version 3.51.17 of the driver.Specifying socketThis one specifies the Unix socket file or Windows named pipe to connect to. Used only for local client connections.Driver={MySQL ODBC 3.51Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;Socket=MySQL;Option=3;On Windows, the socket variable is the name of the named pipe that is used for local client connections. The default value is MySQL.On Unix platforms, the socket variable is the name of the socket file that is used for local client connections. The default is /tmp/mysql.sock.Using SSLDriver={MySQL ODBC 3.51Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;sslca=c:\cacert.pem;sslcert=c:\client-cert.pem;sslkey=c: \client-key.pem;sslverify=1;Option=3;SSLCA specifies the path to a file with a list of trust SSL CAsSSLCERT specifies the name of the SSL certificate file to use for establishing a secure connection.SSLKEY specifies the name of the SSL key file to use for establishing a secure connection. MySQL Connector/ODBC 5.1Type: ODBC DriverUsage:Driver={MySQL ODBC 5.1 Driver}Manufacturer: MySQLMore info about this driver »Customize stringexample values »Local databaseDriver={MySQL ODBC 5.1 Driver};Server=localhost;Database=myDataBase;User=myUsername;Password=myPassword;Option=3;Remote databaseDriver={MySQL ODBC 5.1Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;Option=3;Specifying TCP/IP portDriver={MySQL ODBC 5.1Driver};Server=myServerAddress;Port=3306;Database=myDataBase;User=myUsername; Password=myPassword;Option=3;The driver defaults to port value 3306, if not specified in the connection string, as 3306 is the default port for MySQL.Specifying character setDriver={MySQL ODBC 5.1Driver};Server=myServerAddress;charset=UTF8;Database=myDataBase;User=myUsern ame; Password=myPassword;Option=3;Specifying socketThis one specifies the Unix socket file or Windows named pipe to connect to. Used only for local client connections.Driver={MySQL ODBC 5.1Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;Socket=MySQL;Option=3;On Windows, the socket variable is the name of the named pipe that is used for local client connections. The default value is MySQL.On Unix platforms, the socket variable is the name of the socket file that is used for local client connections. The default is /tmp/mysql.sock.Using SSLDriver={MySQL ODBC 5.1Driver};Server=myServerAddress;Database=myDataBase;User=myUsername;Password=myPassword;sslca=c:\cacert.pem;sslcert=c:\client-cert.pem;sslkey=c: \client-key.pem;sslverify=1;Option=3;SSLCA specifies the path to a file with a list of trust SSL CAsSSLCERT specifies the name of the SSL certificate file to use for establishing a secure connection.SSLKEY specifies the name of the SSL key file to use for establishing a secure connection..NET Framework Data Provider for ODBCType: .NET Framework Wrapper Class LibraryUsage:System.Data.Odbc.OdbcConnectionManufacturer: MicrosoftMore info about this wrapper class library »Customize stringexample values »Bridging to MySQL Connector/ODBC 5.1This is just one connection string sample for the wrapping OdbcConnection class that calls the underlying ODBC Driver. See respective ODBC driver for more connection strings to use with this class.Driver={MySQL ODBC 5.1 Driver};Server=localhost;Database=myDataBase;User=myUsername;Password=myPassword;Option=3;。
opengauss数据库连接串的参考样例
opengauss数据库连接串的参考样例
在OpenGauss数据库中，连接串用于建立与数据库的连接。
连接串通常包括数据库的地址、端口、用户名、密码等信息。
以下是一个OpenGauss数据库连接串的参考样例：
```
jdbc:opengauss://hostname:port/databasename?user=username&password=password
```
其中，各部分的含义如下：
- `jdbc:opengauss://`：表示使用OpenGauss JDBC驱动。
- `hostname`：数据库服务器的主机名或IP地址。
- `port`：数据库服务器的端口号，默认为`5432`。
- `databasename`：要连接的数据库的名称。
- `user`：连接数据库的用户名。
- `password`：连接数据库的密码。
示例：
```plaintext
jdbc:opengauss://localhost:5432/mydatabase?user=myuser&password=mypassword
```
在实际使用时，请替换为你的实际数据库主机名、端口号、数据库名称、用户名和密码。
此外，OpenGauss还支持SSL连接，你可以在连接串中添加SSL相关的配置参数，以加强连接的安全性。
数据库内连接查询语句
数据库内连接查询语句数据库内连接查询语句是数据库中常用的一种查询方法，用于从多个表中检索数据并进行关联。
下面是十个符合要求的数据库内连接查询语句的示例：1. 查询订单表和客户表中的所有匹配记录：SELECT * FROM 订单表 INNER JOIN 客户表 ON 订单表.客户ID = 客户表.客户ID;2. 查询学生表和课程表中的所有匹配记录：SELECT * FROM 学生表 INNER JOIN 课程表 ON 学生表.学生ID = 课程表.学生ID;3. 查询员工表和部门表中的所有匹配记录：SELECT * FROM 员工表 INNER JOIN 部门表 ON 员工表.部门ID = 部门表.部门ID;4. 查询商品表和分类表中的所有匹配记录：SELECT * FROM 商品表 INNER JOIN 分类表 ON 商品表.分类ID = 分类表.分类ID;5. 查询订单表、客户表和商品表中的所有匹配记录：SELECT * FROM 订单表 INNER JOIN 客户表 ON 订单表.客户ID = 客户表.客户ID INNER JOIN 商品表 ON 订单表.商品ID = 商品表.商品ID;6. 查询学生表、课程表和成绩表中的所有匹配记录：SELECT * FROM 学生表 INNER JOIN 课程表 ON 学生表.学生ID = 课程表.学生ID INNER JOIN 成绩表 ON 学生表.学生ID = 成绩表.学生ID;7. 查询员工表、部门表和工资表中的所有匹配记录：SELECT * FROM 员工表 INNER JOIN 部门表 ON 员工表.部门ID = 部门表.部门ID INNER JOIN 工资表 ON 员工表.员工ID = 工资表.员工ID;8. 查询商品表、分类表和库存表中的所有匹配记录：SELECT * FROM 商品表 INNER JOIN 分类表 ON 商品表.分类ID = 分类表.分类ID INNER JOIN 库存表 ON 商品表.商品ID = 库存表.商品ID;9. 查询订单表和客户表中匹配的记录，并按照订单金额升序排序：SELECT * FROM 订单表 INNER JOIN 客户表 ON 订单表.客户ID = 客户表.客户ID ORDER BY 订单表.订单金额 ASC;10. 查询学生表和课程表中匹配的记录，并按照课程名称降序排序：SELECT * FROM 学生表 INNER JOIN 课程表 ON 学生表.学生ID = 课程表.学生ID ORDER BY 课程表.课程名称 DESC;以上是十个符合要求的数据库内连接查询语句的示例，它们可以用于从多个表中检索数据并进行关联。
ASP.NETC#各种数据库连接字符串大全——SQLServer、Oracle、Access
C#各种数据库连接字符串⼤全——SQLServer、Oracle、Access 刚开始学习C#开发项⽬时，长期会为了写⼀个安全的⾼效的数据库连接发愁。
我发现现在很多刚开始学习的朋友和有些做了⼀两年的朋友，也有点犯愁，我就贴上这个代码，给⾃⼰以后做个参考，也给朋友做个学习的参考。
我主要在这⾥统计了.NET项⽬下常⽤的数据库连接字符串：SQLServer、Oracle、Access三种数据库（MySql、SQLLite、Excel、HTML Table等等暂不列⼊）。
⼀、常⽤连接字符串参数说明如需查看详细说明请参见：关键字默认描述Server 或 Data Source N/A要连接的数据库实例的名称或⽹络地址(可以在名称后指定端⼝号),指定本地实例可⽤(Local),如果是SqlExpress(名称\SqlExpress)。
Initial Catalog 或 Database N/A数据库的名称。
User ID 或 UID N/A登录帐户。
Password 或 Pwd N/A帐户登录的密码。
Persist Security Info 'false'当该值设置为 false 或 no（强烈推荐）时，如果连接是打开的或者⼀直处于打开状态，那么安全敏感信息（如密码）将不会作为连接的⼀部分返回。
重置连接字符串将重置包括密码在内的所有连接字符串值。
可识别的值为 true、false、yes 和 no。
Enlist 'false'true 表明连接池程序在创建线程的当前事务上下⽂中⾃动登记连接。
可识别的值为 true、false、yes 和 no。
Connection Lifetime 0当连接被返回到池时，将其创建时间与当前时间作⽐较，如果时间长度（以秒为单位）超出了由 Connection Lifetime 指定的值，该连接就会被销毁。
这在聚集配置中很有⽤（⽤于强制执⾏运⾏中的服务器和刚置于联机状态的服务器之间的负载平衡）。
几种常见的数据库连接方法
几种常见的数据库连接方法一、连接Access数据库1.使用已有DSN的连接字符串进行连接（ODBC）使用DSN进行连接〃导入命名空间using System.Data.Odbc;protected void Page_Load(Object sender,EventArgs e)(〃设置连接字符串String connstr=@"DSN=sample";〃实例化Connection对象OdbcConnection myConnection = new OdbcConnection(connstr);〃执行Open方法打开连接myConnection.Open();〃执行SQL语句OdbcCommand myCommand new OdbcCommand("select * from sampletable",myConnection);〃将查询的结果赋给GridView的数据源gv.DataSource = myCommand.ExecuteReader();〃绑定GridViewgv.DataBind();〃关闭连接myConnection.Close();)2.使用无DSN的连接字符串进行连接（ODBC）不使用DSN进行连接〃导入命名空间using System.Data.Odbc;protected void Page_Load(Object sender,EventArgs e)(〃设置连接字符串String connstr=@"Driver=Microsoft Access Driver (*.mdb);Dbq=c:\sample.mdb;";〃实例化Connection对象OdbcConnection myConnection = new OdbcConnection(connstr);〃执行Open方法打开连接myConnection.Open();〃执行SQL语句OdbcCommand myCommand new OdbcCommand("select * from sampletable",myConnection);〃将查询的结果赋给GridView的数据源gv.DataSource = myCommand.ExecuteReader();〃绑定GridViewgv.DataBind();〃关闭连接myConnection.Close();)3.使用连接字符串进行连接(OLEDB) Data Provider 支持的OLEDB Provider：SQLOLEDB：用来访问SQL Server数据库MSDAORA：用来访问Oracle数据库Microsoft.Jet.OLEDB.4.0：用来访问Access 数据库。
数据库外连接语句
数据库外连接语句
数据库外连接语句
外连接（Outer Joins）被用来从一个（或多个）表中取得与另一个表中的数据匹配的行。
另外，它还可以从表中取得非匹配行。
一．左外连接（LEFT OUTER JOIN）
例如：
SELECT stName, Employees.FirstName, Orders.OrderID
FROM Employees LEFT OUTER JOIN Orders ON
Employees.EmployeeID = Orders.EmployeeID
这条语句会返回所有员工的订单信息，如果该员工没有订单，系统也会返回该员工的信息，只是订单号为空。
二．右外连接（RIGHT OUTER JOIN）
例如：
SELECT stName, Employees.FirstName, Orders.OrderID
FROM Employees RIGHT OUTER JOIN Orders ON
Employees.EmployeeID = Orders.EmployeeID
这条语句会返回所有订单信息，如果该订单没有员工，系统也会返回该订单的信息，只是员工的信息为空。
三．完全外连接（FULL OUTER JOIN）
例如：
SELECT stName, Employees.FirstName, Orders.OrderID
FROM Employees FULL OUTER JOIN Orders ON
Employees.EmployeeID = Orders.EmployeeID
这条语句会返回所有员工及订单信息，如果没有匹配的信息，系统也会返回相应的信息，只是关联列对应的信息为空。
连接数据库查询语句
连接数据库查询语句
连接数据库并进行查询通常需要使用特定的数据库查询语句，这取决于你所使用的数据库管理系统。
以下是一些常见的数据库查询语句示例：
1. 对于MySQL数据库：
连接到数据库，`mysql -u 用户名 -p 密码 -h 主机名数据库名`。
查询数据，`SELECT FROM 表名 WHERE 条件`。
2. 对于Oracle数据库：
连接到数据库，`sqlplus 用户名/密码@主机名:端口/服务名`。
查询数据，`SELECT FROM 表名 WHERE 条件`。
3. 对于SQL Server数据库：
连接到数据库，`sqlcmd -S 服务器名 -U 用户名 -P 密码
-d 数据库名`。
查询数据，`SELECT FROM 表名 WHERE 条件`。
4. 对于PostgreSQL数据库：
连接到数据库，`psql -h 主机名 -U 用户名 -d 数据库名`。
查询数据，`SELECT FROM 表名 WHERE 条件`。
无论使用哪种数据库管理系统，查询语句的核心部分都是
`SELECT FROM 表名 WHERE 条件`，其中`SELECT`用于选择要检索
的列，`FROM`用于指定要检索数据的表，`WHERE`用于过滤检索的数据。
在使用数据库查询语句时，需要确保对数据库有足够的权限，
并且要谨慎处理敏感信息，以免造成数据泄露或损坏。
同时，还应
该考虑到查询的性能，避免对数据库造成过大的负担。
总之，连接数据库并进行查询是数据库管理和开发中非常常见
的操作，需要根据具体的情况选择合适的数据库查询语句，并且要注意安全和性能方面的考虑。
Oracle数据库连接字符串
Oracle数据库连接字符串(经典大全)2009-08-21 14:36ODBC新版本Driver={Microsoft ODBC for Oracle};Server=myServerAddress;Uid=myUsername;Pwd=myPassword;旧版本Driver={Microsoft ODBC Driver for Oracle};ConnectString=OracleServer.world;Uid=myUsername;Pwd=myPassword; OLE DB, OleDbConnection (.NET)标准连接此连接字符串适用了微软的驱动。
Provider=msdaora;Data Source=MyOracleDB;User Id=myUsername;Password=myPassword;受信连接Provider=msdaora;Data Source=MyOracleDB;Persist Security Info=False;Integrated Security=Yes;标准连接由Oracle提供的驱动。
Provider=OraOLEDB.Oracle;Data Source=MyOracleDB;User Id=myUsername;Password=myPassword;受信连接Provider=OraOLEDB.Oracle;Data Source=MyOracleDB;OSAuthent=1;Oracle.DataAccess.Client.OracleConnectionData Source=TORCL;User Id=myUsername;Password=myPassword;标准安全连接Data Source=TORCL;Integrated Security=SSPI;使用而不使用tnsnames.oraDataSource=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(C ONNECT_DATA=(SERVER=DEDICA TED)(SERVICE_NAME=MyOracleSID)));UserId=myUsername;Password=myPassword;OracleConnection, Oracle Data Provider, , System.Data.OracleClient.OracleConnection标准Data Source=MyOracleDB;Integrated Security=yes;用于8i RC3及以后的版本指定用户名和密码Data Source=MyOracleDB;User Id=myUsername;Password=myPassword;Integrated Security=no;用于8i RC3及以后的版本忽略tnsnames.ora另一种不需要使用DSN的连接方式。
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数据库的连接串在数据库的各种应用程序开发中，连接数据库是数据库应用程序开发的第一步，同时也是最重要的一步。
而对于不同的数据库他们的连接模式各有不同，对应的连接串也不同。
程序员可能都有这样的经历，有时不知道连接数据库所需要的连接串究竟如何写或者经常写错而导致不能正确访问数据库。
当然很多编程工具能够通过可视化的界面直接产生正确的连接字符串，但字符串中各个参数的具体含义也不清楚，经常混淆。
本文就针对大部分常用数据库列举出不同连接方法所需要的连接字符串并加以说明，以便程序员参考！Sql Server· ODBCo 标准连接（Standard Security）:"Driver={SQL Server};Server=Aron1;Database=pubs;Uid=sa;Pwd=asdasd;" 1）当服务器为本地时Server可以使用(local);"Driver={SQLServer};Server=(local);Database=pubs;Uid=sa;Pwd=asdasd;"2）当连接远程服务器时，需指定地址、端口号和网络库"Driver={SQLServer};Server=130.120.110.001;Address=130.120.110.001,1052;Network= dbmssocn;Database=pubs;Uid=sa;Pwd=asdasd;"注：Address参数必须为IP地址，而且必须包括端口号o 信任连接（Trusted connection）: （Microsoft Windows NT 集成了安全性）"Driver={SQLServer};Server=Aron1;Database=pubs;Trusted_Connection=yes;"或者"Driver={SQL Server};Server=Aron1;Database=pubs; Uid=;Pwd=;"o 连接时弹出输入用户名和口令对话框:Conn.Properties("Prompt") = adPromptAlwaysConn.Open "Driver={SQL Server};Server=Aron1;DataBase=pubs;"· OLE DB, OleDbConnection (.NET)o 标准连接（Standard Security）:"Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;UserId=sa;Password=asdasd;"o 信任连接（Trusted connection）:"Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;Integrated Security=SSPI;"(如果连接一个具体的已命名SQLServer实例,使用Data Source=Servere Name\Instance Name;但仅适用于SQLServer2000)例如：”Provider=sqloledb;DataSource=MyServerName\MyInstanceName;InitialCatalog=MyDatabaseName;UserId=MyUsername;Password=MyPassword;”o 连接时弹出输入用户名和口令对话框:Conn.Provider = "sqloledb"Conn.Properties("Prompt") = adPromptAlwaysConn.Open "Data Source=Aron1;Initial Catalog=pubs;"o 通过IP地址连接:"Provider=sqloledb;Data Source=190.190.200.100,1433;NetworkLibrary=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;" (DBMSSOCN=TCP/IP代替Named Pipes, Data Source的末尾是需要使用的端口号(缺省为1433))· SqlConnection (.NET)o 标准连接（Standard Security）:"Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;" 或者"Server=Aron1;Database=pubs;UserID=sa;Password=asdasd;Trusted_Connection=False"(这两个连接串的结果相同)o 信任连接（Trusted connection）:"Data Source=Aron1;Initial Catalog=pubs;Integrated Security=SSPI;"或者"Server=Aron1;Database=pubs;Trusted_Connection=True;"(这两个连接串的结果相同)(可以用serverName\instanceName代替Data Source，取值为一个具体的SQLServer实例,但仅适用于SQLServer2000)o 通过IP地址连接:"Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;"(DBMSSOCN=TCP/IP代替Named Pipes, Data Source的末尾是需要使用的端口号(缺省为1433))o SqlConnection连接的声明:C#:using System.Data.SqlClient;SqlConnection SQLConn = new SqlConnection();SQLConn.ConnectionString="my connectionstring";SQLConn.Open();:Imports System.Data.SqlClientDim SQLConn As SqlConnection = New SqlConnection()SQLConn.ConnectionString="my connectionstring"SQLConn.Open()· Data Shapeo MS Data Shape"Provider=MSDataShape;Data Provider=SQLOLEDB;DataSource=Aron1;Initial Catalog=pubs;User ID=sa;Password=asdasd;"·更多o 如何定义使用哪个协议§举例:"Provider=sqloledb;Data Source=190.190.200.100,1433;NetworkLibrary=DBMSSOCN;Initial Catalog=pubs;User ID=sa;Password=asdasd;" 名称网络协议库dbnmpntw Win32 Named Pipesdbmssocn Win32 Winsock TCP/IPdbmsspxn Win32 SPX/IPXdbmsvinn Win32 Banyan Vinesdbmsrpcn Win32 Multi-Protocol (Windows RPC)§重要提示当通过SQLOLEDB提供者进行连接时使用以下语法：Network Library=dbmssocn但通过MSDASQL提供者进行连接时使用以下语法：Network=dbmssocno 所有SqlConnection连接串属性§下表显示了 SqlConnection对象的所有连接串属性. 其中大多数的属性也在ADO中使用.所有属性和描述来自于msdn.名称缺省值描述Application Name 应用程序名称或者当没有提供应用程序时为.Net SqlClient数据提供者AttachDBFilename或者extended properties或者Initial File Name 主要文件的名字，包括相关联数据库的全路径。
数据库名字必须通过关键字''database''来指定。
Connect Timeout或者Connection Timeout 15 在中止连接请求，产生错误之前等待服务器连接的时间（以秒为单位）Connection Lifetime 0 当一个连接返回到连接池，当前时间与连接创建时间的差值，如果时间段超过了指定的连接生存时间，此连接就被破坏。
它用于聚集设置中在运行服务器和准备上线的服务器之间强制负载平衡。
Connection Reset ''true'' 当连接从连接池移走时决定是否重置数据库连接。
当设置为''false''时用于避免获得连接时的额外服务器往复代价。
Current Language SQL Server语言记录名称Data Source或Server或Address或Addr或Network Address 要连接的SQL Server实例的名字或者网络地址Enlist ''true'' 为真时，连接池自动列出创建线程的当前事务上下文中的连接。
Initial Catalog或Database 数据库名Integrated Security或者Trusted_Connection ''false'' 连接是否为信任连接。
其取值为''true''，''false''和''sspi''（等于''true''）.Max Pool Size 100 连接池中允许的最大连接数Min Pool Size 0 连接池中允许的最小连接数Network Library或Net ''dbmssocn'' 网络库用于建立与一个SQL Server 实例的连接。