mythp

摘要： create table a(id varchar(20) primary key,password varchar(20) not null)create table b(id int identity(1,1) primary key,name varchar(50) not null,userId varchar(20),foreign key (userId) references a(id) on delete cascade)表B创建了外码userId 对应A的主码ID，声明了级联删除测试数据：insert a values ('11','aaa') 阅读全文