《MySQL必知必会》[04] 表的操作和视图的使用

CREATE TABLE R (
  A1<数据类型>,
  A1<数据类型>,
  ...
  An<数据类型>
);

CREATE TABLE vendors
(
  vend_id      int      NOT NULL AUTO_INCREMENT,
  vend_name    char(50) NOT NULL,
  vend_state   char(5)  NULL,
  vend_country char(50) NULL DEFAULT ‘China‘,
  PRIMARY KEY (vend_id)
) ENGINE=InnoDB;

ALTER TABLE R 具体的更改操作;

//添加列
ALTER TABLE vendors
ADD vend_phone CHAR(20);
//删除列
ALTER TABLE vendors
DROP COLUMN vend_phone;
//添加外键
ALTER TABLE orderitems
ADD CONSTRAINT fk_orderitems_orders
FOREIGN KEY (order_num) REFERENCES orders (order_num);

DROP TABLE R;

RENAME TABLE R1 TO R2;

CREATE VIEW <视图名> AS <子查询>;