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;