MySql创建表

create table Customers
(
    CustomersID int unsigned not null auto_increment primary key, //主键,自曾
    Name char(50) not null,
    Address char(120) not null,
    City char(30) not null
)

  
    

   
      1 
   
     create
   
      
   
     table
   
      orders

   
      2 
   
     (

   
      3 
   
      orderID 
   
     int
   
      unsigned 
   
     not
   
      
   
     null
   
      auto_increment 
   
     primary
   
      
   
     key
   
     ,

   
      4 
   
      customerID 
   
     int
   
      unsigned 
   
     not
   
      
   
     null
   
     ,

   
      5 
   
      amount 
   
     float
   
     (
   
     6
   
     ,
   
     2
   
     ),

   
      6 
   
      date date 
   
     not
   
      
   
     null
   
     

   
      7 
   
     )

   
      8 
   
     

   
      9 
   
      
   
     create
   
      
   
     table
   
      books

   
     10 
   
     (

   
     11 
   
      ISBN 
   
     char
   
     (
   
     13
   
     ) 
   
     not
   
      
   
     null
   
      
   
     primary
   
      
   
     key
   
     ,

   
     12 
   
      author 
   
     char
   
     (
   
     50
   
     ),

   
     13 
   
      title 
   
     char
   
     (
   
     50
   
     ),

   
     14 
   
      price 
   
     float
   
     (
   
     4
   
     ,
   
     2
   
     ) 
   
     //
   
     指定显示宽度和小数点后的位数

   
     15 
   
     )

   
     16 
   
     

   
     17 
   
      
   
     create
   
      
   
     table
   
      order_itme

   
     18 
   
     (

   
     19 
   
      orderID 
   
     int
   
      unsigned 
   
     not
   
      
   
     null
   
     ,

   
     20 
   
      isbn 
   
     char
   
     (
   
     13
   
     ) 
   
     not
   
      
   
     null
   
     ,

   
     21 
   
      quantity 
   
     tinyint
   
      unsigned,

   
     22 
   
      
   
     primary
   
      
   
     key
   
     (orderID,isbn) 
   
     //
   
     使用多列组成主键 

   
     23 
   
      

   
     24 
   
     )

   
     25 
   
     

   
     26 
   
     
   
     create
   
      
   
     table
   
      book_reviews

   
     27 
   
     (

   
     28 
   
      isbn 
   
     char
   
     (
   
     13
   
     ) 
   
     not
   
      
   
     null
   
      
   
     primary
   
      
   
     key
   
     ,

   
     29 
   
      review 
   
     text
   
     

   
     30 
   
     )