#创建数据库
CREATE DATABASE s4day65 DEFAULT CHARSET utf8;
#班级表
CREATE TABLE class (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
title CHAR(20)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
#学生表 有一个指向班级表的外键
CREATE TABLE student (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
NAME CHAR(20),
class_id INT,
CONSTRAINT fk_s_c FOREIGN KEY (class_id) REFERENCES class(id)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
#教师表
CREATE TABLE teacher (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
NAME CHAR(20)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
#教师和班级关系表
CREATE TABLE teacher2class(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
class_id INT,
teacher_id INT,
CONSTRAINT fk_tc_c FOREIGN KEY (class_id) REFERENCES class(id),
CONSTRAINT fk_tc_t FOREIGN KEY (teacher_id) REFERENCES teacher(id)
)ENGINE=INNODB DEFAULT CHARSET=utf8;