1 create table demo1_zhujian (
2 id int primary key auto_increment,
3 name varchar(10));
2、新建外键table
1 create table demo2_waijian (
2 id int primary key auto_increment,
3 _id int not null default 0,
4 name varchar(10),
5 index (_id),
6 FOREIGN KEY (_id) REFERENCES demo1_zhujian(id) ON DELETE CASCADE ON UPDATE CASCADE);
7
8 create table demo3_waijian (
9 id int primary key auto_increment,
10 _id int not null default 0,
11 name varchar(10),
12 index (_id),
13 FOREIGN KEY (_id) REFERENCES demo1_zhujian(id) ON DELETE CASCADE ON UPDATE CASCADE);