Question

mysql 不能添加外键 1215cu

drop table if exists company;

drop table if exists friends;

drop table if exists image_text;

drop table if exists news;

drop table if exists newstype;

drop table if exists user;

drop table if exists video;

create temporary table company
(
id int(8) not null,
name varchar(500),
path varchar(500),
primary key (id)
);

create temporary table friends
(
id int(8) not null,
content varchar(500),
image0 varchar(500),
image1 varchar(500),
image2 varchar(500),
user_id int(8),
primary key (id)
);

create temporary table image_text
(
id int(8) not null,
title varchar(500),
image varchar(500),
news_id int(8),
primary key (id)
);

create temporary table news
(
id int(8) not null,
title varchar(500),
tetail text,
image0 varchar(500),
image1 varchar(500),
image2 varchar(500),
time varchar(500),
type_id int(8),
company_id int(8),
primary key (id)
);

create temporary table newstype
(
id int(8) not null,
type varchar(100),
primary key (id)
);

create temporary table user
(
id int(8) not null,
name varchar(100),
qq varchar(200),
primary key (id)
);

create temporary table video
(
id int(8) not null,
path varchar(500),
primary key (id)
);

alter table friends add constraint FK_Reference_4 foreign key (user_id)
references user (id) on delete restrict on update restrict;

alter table image_text add constraint FK_Reference_2 foreign key (news_id)
references news (id) on delete restrict on update restrict;

alter table news add constraint FK_Reference_3 foreign key (company_id)
references company (id) on delete restrict on update restrict;

alter table news add constraint FK_Reference_5 foreign key (type_id)
references newstype (id) on delete restrict on update restrict;
这是报的错

[SQL]

alter table friends add constraint FK_Reference_4 foreign key (user_id)
references user (id) on delete restrict on update restrict;
[Err] 1215 - Cannot add foreign key constraint

Answer 1

可以先删除外键关联，执行结尾再加上