...操作语言(Data Manipulation Language)DCL数据控制语言(Data Control Language)TCL事务控制语言（Transaction Control Language）数据库模式定义语言DDL(Data Definition Language)，是用于描述数据库中要存储的现实世界实体的语言。
abstract:A Transaction Control Language (TCL) is a computer language and a subset of SQL, used to control transactional processing in a database. A transaction is logical unit of work that comprises one or more SQL statements, usually a group of Data Manipulation Language (DML) statements.