1 视图的引入
2 视图的作用
3 创建视图
(1)在单表上创建视图
CREATE VIEW v1 AS SELECT * FROM t_book;
CREATE VIEW v2 AS SELECT bookName,price FROM t_book;
CREATE VIEW v3(b,p) AS SELECT bookName,price FROM t_book;
SELECT * FROM v1;
SELECT * FROM v2;
SELECT * FROM v3;
(2)在多表上创建视图
CREATE VIEW v4 AS SELECT bookName,bookTypeName FROM t_book,t_booktype WHERE t_book.bookTypeId=t_booktype.id;
CREATE VIEW v5 AS SELECT tb.bookName,tby.bookTypeName FROM t_book tb,t_booktype tby WHERE tb.bookTypeId=tby.id;
SELECT * FROM v4;
SELECT * FROM v5;
4 查看视图
DESC v5;
SHOW TABLE STATUS LIKE 'v5';
SHOW TABLE STATUS LIKE 't_book';
SHOW CREATE VIEW v5;
5 修改视图
(1)CREATE OR REPLACE VIEW语句修改视图
CREATE OR REPLACE VIEW v1(bookName,price) AS SELECT bookName,price FROM t_book;
(2)ALTER VIEW 语句修改视图
ALTER VIEW v1 AS SELECT * FROM t_book;
6 更新视图
(1)插入(INSERT)
INSERT INTO v1 VALUES(NULL,'java good',120,'feng',1);
(2)更新(UPDATE)
UPDATE v1 SET bookName='java very good',price=200 WHERE id=5;
(3)删除(DELETE)
DELETE FROM v1 WHERE id=5;
7 删除视图
DROP VIEW IF EXISTS v4;