未分类题

已知职工和职工亲属两个关系,当职工调出时,应该从职工关系中删除该职工的元组,同时在职工亲属关系中删除对应的亲属元组,在SQL语言中,定义这个完整性约束的短语是( )

A ON DELETE ALL
B ON DELETE RESTRICT
C ON DELETE SET NULL
D ON DELETE CASCADE


【参考答案】

参考D