数据库原理基本概念英文解释

数据库原理基本概念

Basic concepts of database theory

一、数据---Data

Data is everything.

Data can exist in a variety of forms -- as digital numbers, text, image, sound, video and etc.

二、数据库---Database

A database is a repository for a collection of computerized data files.

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies). The term "database" refers both to the way its users view it, and to the logical and physical materialization of its data, content, in files, computer memory, and computer data storage.

三、数据库系统---DBS(Database System)

A database system is a term that is typically used to encapsulate the constructs of a data model, database Management system (DBMS) and database.

四、数据库管理系统---DBMS(Database Management

System)

A database management system (DBMS) is a software package with computer programs that control the creation, maintenance, and the use of a database. It allows organizations to conveniently develop databases for various applications by database administrators (DBAs) and other specialists.

A collection of programs that enables you to store, modify, and extract information from a database.

五、数据库管理员---DBA(Database Administrator)

A database administrator is a person responsible for the design, implementation, maintenance and repair of an organization's database.

六、模式---Schema

A database schema of a database system is its structure described in a formal language supported by the database management system (DBMS) and refers to the organization of data to create a blueprint of how a database will be constructed.

In other words, schema is the structure of the database that defines the objects in the database.

七、内模式---Internal Schema

Internal Schema: storage schema

– Describes how data is stored and what the physical structure

of data is.

– Totally dependent on particular implementation.

– There is only one internal schema in a DB.

八、外模式---External Schema

External Schema: user schema or subschema

– Interface between users and DBS

– Describes the logical structure of some local data oriented to

some applications and users

– There may be many external schemata in a DB.

九、三级模式---Three Levels of Schema

-Physical level: describes how a record (e.g., customer) is stored.

-Logical level: describes data stored in database, and the

relationships among the data.

-View level: application programs hide details of data types. Views can also hide information (such as an e mployee’s salary)

for security purposes.

十、映像---Mapping

Data mapping is the process of creating data element mappings between two distinct data models. Data mapping is used as a first step for a wide variety of data integration tasks including: