teacher(
2 t_id INT PRIMARY KEY AUTO_INCREMENT,
3 t_name VARCHAR(20)
4 );
5 CREATE TABLE class(
6 c_id INT PRIMARY KEY AUTO_INCREMENT,
7 c_name VARCHAR(20),
8 teacher_id INT
9 );
10 ALTER TABLE class ADD CONSTRAINT fk_teacher_id FOREIGN KEY (teacher_id) REFERENCES teacher(t_id);
11
12 INSERT INTO teacher(t_name) VALUES('teacher1');
13 INSERT INTO teacher(t_name) VALUES('teacher2');
14
15 INSERT INTO class(c_name, teacher_id) VALUES('class_a', 1);
16 INSERT INTO class(c_name, teacher_id) VALUES('class_b', 2);
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