全部SQL语言，实现了创建数据库、数据表、定义索引、视图等语句。



完整性约束包括：主键约束、外键约束、非空约束、规则、默认值、触发器等。



数据表的操纵语句：包括数据插入、数据删除、数据修改操作语句。-All SQL language, to achieve the creation of databases, tables, define indexes, views, and other statements. Integrity constraints include: primary key constraints, foreign key constraints, not null constraints, rules, defaults, triggers, etc.. Data table manipulation statements include: data insertion, data deletion, data modification operations statements.