mysql - 错误代码: 1215 : Cannot add foreign key constrain MYSql

Question

我不太懂编程，如果我的问题看起来很陈词滥调，那么抱歉。每当我尝试此程序时，我都会收到“错误代码:1215:无法添加外键约束 MYSql”

create table department(dept_name varchar(20) primary key,
building varchar(15),
budget numeric(12,2));
create table course(course_id varchar (7),
title varchar (50),
dept_name varchar (20),
credits numeric (2,0),
primary key (course_id),
foreign key (dept_name) references department);

有人可以帮我吗

Answer 1

您尚未定义要引用的 dept_name 的哪一列。请尝试这个:

create table department(dept_name varchar(20) primary key,
building varchar(15),
budget numeric(12,2));
create table course(course_id varchar (7),
title varchar (50),
dept_name varchar (20),
credits numeric (2,0),
primary key (course_id),
foreign key (dept_name) references department(dept_name));