单项选择题
A.主码约束B.外码约束C.域约束D.强制存取权限控制
A.CREATE ASSERTIONB.FOREIGN KEYC.CREATE ROLED.CREATE TRIGGER
A.类型级约束B.属性级约束C.关系级约束D.数据库级约束
A.DOMAINB.ASSERTIONC.CONSTRAINTD.TRIGGER
A.CREATE ASSERTIONB.CREATE TRIGGERC.CREATE ROLED.CREATE DOMAIN
A.断言B.自主存取权限控制C.用户标识与密码D.强制存取权限控制
A.CASCADEB.RESTRICTC.SET NULLD.SET DEFAULT
A.SQLCODEB.主语言变量C.游标D.数组
A.CREATE DATABASEB.CREATE TABLEC.CREATE VIEWD.CREATE INDEX