sql statement to create a foreign key association

To create a table, for example student teacher: student idassociation of teacherstid

Student table: student

teacher table: teacher

sql statement:

USE school;

CREATE TABLE student(
id INT(10) NOT NULL PRIMARY KEY,
NAME VARCHAR(30) DEFAULT NULL,
tid INT(10) DEFAULT NULL,
KEY `fktid` (`tid`),
CONSTRAINT `fktid` FOREIGN KEY(`tid`) REFERENCES `teacher` (`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8

INSERT INTO student VALUES(1,'小明',1);
INSERT INTO student VALUES(2,'小红',1);
INSERT INTO student VALUES(3,'小刚',1);
INSERT INTO student VALUES(4,'小王',1);
INSERT INTO student VALUES(5,'小智',1);

SELECT * FROM student;

CREATE TABLE teacher (
id INT(10) PRIMARY KEY NOT NULL,
NAME VARCHAR (30) DEFAULT NULL
)ENGINE=INNODB DEFAULT CHARSET=utf8


INSERT INTO teacher VALUES(1,'陈老师');
SELECT * FROM teacher;

Important: Foreign key related sentences can only be written by hand!

KEY `fktid` (`tid`),
CONSTRAINT `fktid` FOREIGN KEY(`tid`) REFERENCES `teacher` (`id`)