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create table movie(
movieTitle varchar(40)
not null
, yearReleased year
check (not year > year(current_date))
, movieLength int(3)
null
, constraint coPKmovie
primary key (movieTitle, yearReleased)
);
create table person(
personName varchar(40)
not null
, secondName varchar(40)
not null
, dateOfBirth datetime
not null
, yearCareerStarted year
not null
check (not year > year(current_date))
, bornCountry char(03)
not null
, constraint coPKperson
primary key (personName, secondName)
);
create table participant(
partPersonName varchar(40)
not null
, partSecondName varchar(40)
not null
, movieTitle varchar(40)
not null
, jobTitle varchar(30)
not null
, constraint coPKpart
primary key (partPersonName, partSecondName, movieTitle, jobTitle)
);
alter table participant
add constraint partFKname foreign key (partPersonName)
references person (personName)
, add constraint partFKSecond foreign key (partSecondName)
references person (secondName)
, add constraint partFKmovie foreign key (movieTitle)
references movie (movieTitle)
on delete cascade
on update cascade;
有人可以解释为什么我总是得到一个错误,而我想从表参与者,partSecondName到表person,secondName创建外键。我不想听到为什么我不在数据库中使用任何ID,我只是在没有他们的情况下练习。提前致谢! :)MySQL,不能创建外键
什么是错误? – Mihai
这个人的FK是错误的,你应该同时对名字和第二个名字进行单独的约束,而不是单独的约束。 –
非常感谢你Matteo Tassinari,它现在工作!哦,现在我会知道:)谢谢:) –