Oracle数据库中的表-SQL语言基础

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文件名称：Oracle数据库中的表-SQL语言基础
文件大小：5.26MB
文件格式：PPT
更新时间：2021-04-25 19:38:28
SQL 基础 Oracle数据库中的表 * 用户表 由用户创建和维护的一系列表的集合 包含用户的信息 数据字典 由Oracle 服务器创建和维护的一系列表的集合 包含数据库的信息 * Tables in the Oracle Database User tables are tables created by the user, such as EMP. There is another collection of tables and views in the Oracle database known as the data dictionary. This collection is created and maintained by the Oracle Server and contains information about the database. All data dictionary tables are owned by the SYS user. The base tables are rarely accessed by the user because the information in them is not easy to understand. Therefore, users typically access data dictionary views because the information is presented in a format that is easier to understand. Information stored in the data dictionary include names of the Oracle Server users, privileges granted to users, database object names, table constraints, and auditing information. There are four categories of data dictionary views; each category has a distinct prefix which reflects their intended use.