摘要：--删除外键语法：alter table 表名 drop constraint 外键约束名如：alter table Stu_PkFk_Sc drop constraint FK_salter table Stu_PkFk_SC drop constraint FK_c--添加外键语法：alter table 表名 add constraint 外键约束名 foreign key(列名) references 引用外键表(列名)如：alter table Stu_PkFk_Scadd constraint Fk_sforeign key (sno)references Stu_PkFk_S(s 阅读全文