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;