在我粘贴的mysql代码中,第二个外来actor_id_FK无法添加错误(1215无法添加外键约束)。问题出在哪里?
create table castings
(
movieid int,
actorid int,
primary key (movieid, actorid)
);
create table movies
(
id int primary key
);
create table actors
(
id int primary key
);
alter table movies
add constraint movies_id_FK
foreign key (id) references castings(movieid);
alter table actors
add constraint actors_id_FK
foreign key (id) references castings(actorid);
答案 0 :(得分:0)
您对外键的概念向后。该定义在 other 表中,而不是在定义主键的位置。所以:
alter table castings add constraint fk_castings_movie_id
foreign key (movieid) references movies(id);