数据库之多表练习

CREATE TABLE clify (

cid INT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(15)

);SELECT *FROM clify;INSERT INTO clify VALUES (NULL,'自然风景'),(NULL,'城市风景'),(NULL,'历史风景');CREATE TABLE line (

rid INT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(15),
price INT,
cid_id INT,
CONSTRAINT cid_rid_id FOREIGN KEY line(cid_id) REFERENCES clify(cid)

);SELECT * FROM line;INSERT INTO line VALUES (NULL,'长白山',5000,1),(NULL,'万达广场',1000,2),(NULL,'伪满皇宫',500,3);CREATE TABLE USER (

id INT,
NAME VARCHAR(10),
PASSWORD INT

);ALTER TABLE USER MODIFY id INT PRIMARY KEY AUTO_INCREMENT SELECT * FROM USER;INSERT INTO USER VALUES (NULL,'张无忌',18),(NULL,'郭靖',38),(NULL,'令狐冲',20);CREATE TABLE line_user(

rid_id INT,
user_id INT,
CONSTRAINT rid_user_id FOREIGN KEY line_user(rid_id) REFERENCES line(rid),
CONSTRAINT user_rid_id FOREIGN KEY line_user(user_id) REFERENCES USER(id)

);INSERT INTO line_user VALUES (1,1),(2,2),(3,3);