问题描述
我的代码:
create table courses(
id SERIAL PRIMARY KEY
)
----------------------
create table teachers(
id SERIAL PRIMARY KEY
)
----------------------
CREATE TABLE assignments(
id SERIAL PRIMARY KEY,given_date TIMESTAMP,deadline TIMESTAMP,FOREIGN KEY(course_id) REFERENCES courses(id),FOREIGN KEY(teacher_id) REFERENCES teachers(id),pass_mark INT,full_mark INT,description TEXT,assignment_file VARCHAR(100)
);
错误:
column "course_id" referenced in foreign key constraint does not exist
sql state: 42703
在课程和教师表的 id 中插入数据后,我尝试运行第三个创建表代码,但没有变化。
解决方法
您不能引用这样的列。首先添加要创建外键的列,然后引用它。
create table courses(
id SERIAL PRIMARY KEY
);
----------------------
create table teachers(
id SERIAL PRIMARY KEY
);
----------------------
CREATE TABLE assignments(
id SERIAL PRIMARY KEY,given_date TIMESTAMP,deadline TIMESTAMP,course_id INT,teacher_id INT,pass_mark INT,full_mark INT,description TEXT,assignment_file VARCHAR(100),FOREIGN KEY(course_id) REFERENCES courses(id),FOREIGN KEY(teacher_id) REFERENCES teachers(id)
);