SQL is divided into three major parts. Data manipulation language (DML) is used to store and retrieve data from the database. Data description language (DDL) is used to define the structure of the data. Data control language (DCL) is used to restrict access to data by certain users. ...
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A slash (/)on a line by itself also tells SQL*Plus that you wish to run the command. Press Return at the end of the last line of the command. SQL*Plus prompts you with another line number. Type a slash and press Return again or click Execute. SQL*Plus executes the command and sto...
Throughthe SQL DML commands UPDATE, INSERT, and DELETE--which can be used independently or within a PL/SQL block--specify changes you wish to make to the information stored in the database. These changes are not made permanent until you enter a SQL COMMITcommand or a SQL DCL or DDL comm...
数据库的组织模式:层次型数据结构网状型数据结构关系型数据结构(MySQL)非关系型数据结构(NoSQL)关系型数据结构图示上图描述了从用户层到物理层的工作结构。 mysql DDL DML DCL 原创 2014-04-09 13:59:08 6939 阅读 1收藏 Linux学习笔记:awk详细用法 一、基础用法awk:报告生成工具;把文件中读取到的每一行的...