mysql (一.建表)

CREATE TABLE t_book_type(
id INT PRIMARY KEY  AUTO_INCREMENT,
bookTypeName VARCHAR(20),
bookTypeDesc VARCHAR(200)
);


CREATE TABLE t_book(
id INT PRIMARY KEY  AUTO_INCREMENT,
bookName VARCHAR(20),
author VARCHAR(10),
price DECIMAL(6,2),
bookTypeId INT  ,
CONSTRAINT `fk` FOREIGN KEY(`bookTypeId`) REFERENCES `t_book_type`(`id`)

);

desc t_bookType;


show create table t_bookType;


alter table t_book rename t_book2;




alter table t_book change bookName bookName2 varchar(20);


alter table t_book add testField int first ;


alter table t_book drop testField;


drop table t_bookType;


drop table t_book;