mysql - MySQL错误1005-外键不起作用

Question

我收到错误代码1005，这意味着我的外键有问题吗？谁能向我解释！

CREATE SCHEMA test;
Use test;

CREATE TABLE student
(
stud_id INT(7) NOT NULL , 
stud_name VARCHAR(30) NOT NULL , 
PRIMARY KEY (stud_id)
);
CREATE TABLE subject
(
subj_code VARCHAR(7) NOT NULL ,   
PRIMARY KEY (subj_code)
);
CREATE TABLE grade
(
stud_id INT(7) NOT NULL , 
subj_code VARCHAR(7) NOT NULL , 
semester INT(1) NOT NULL , 
year YEAR(4) NOT NULL , 
grade VARCHAR(4) NOT NULL , 
PRIMARY KEY (stud_id, subj_code, semester, year) ,
FOREIGN KEY (stud_id) REFERENCES student(student_id)
);
CREATE TABLE subj_enrolment
(
stud_id INT(7) NOT NULL , 
subj_code VARCHAR(7) NOT NULL , 
semester INT(1) NOT NULL , 
year YEAR(4) NOT NULL , 
comment VARCHAR(300) , 
PRIMARY KEY (stud_id, subj_code, semester, year) ,
FOREIGN KEY (stud_id) REFERENCES student(student_id) ,
FOREIGN KEY (subj_code) REFERENCES subject(subject_code)
);

任何帮助是极大的赞赏！

Answer 1

您为引用使用了错误的列名student_id不是学生表中的列名，它必须是stud_id。 subject_code也是如此。我已更正它们并在下面发布。

CREATE SCHEMA test;
Use test;

CREATE TABLE student
(
 stud_id INT(7) NOT NULL , 
 stud_name VARCHAR(30) NOT NULL , 
 PRIMARY KEY (stud_id)
);
CREATE TABLE subject
(
 subj_code VARCHAR(7) NOT NULL ,   
 PRIMARY KEY (subj_code)
);
CREATE TABLE grade
(
 stud_id INT(7) NOT NULL , 
 subj_code VARCHAR(7) NOT NULL , 
 semester INT(1) NOT NULL , 
 year YEAR(4) NOT NULL , 
 grade VARCHAR(4) NOT NULL , 
 PRIMARY KEY (stud_id, subj_code, semester, year) ,
 FOREIGN KEY (stud_id) REFERENCES student(stud_id )
);
CREATE TABLE subj_enrolment
(
 stud_id INT(7) NOT NULL , 
 subj_code VARCHAR(7) NOT NULL , 
 semester INT(1) NOT NULL , 
 year YEAR(4) NOT NULL , 
 comment VARCHAR(300) , 
 PRIMARY KEY (stud_id, subj_code, semester, year) ,
 FOREIGN KEY (stud_id) REFERENCES student(student_id) ,
 FOREIGN KEY (subj_code) REFERENCES subject(subj_code )
);