数据库练习（1）——建立数据库

• 代码区：

create table Salvaging
(  prj_num char(8) primary key,
   prj_name varchar(50),
   start_date datetime,
   end_date datetime,
   prj_status bit,
);

create table Stock
(  mat_num char(8) primary key,
   mat_name varchar(20) not null,
   speci varchar(20) not null,
   warehouse char(20),
   amount int,
   unit decimal(18,2),
   total as([amount]*[unit]),
   check(mat_num like '[m][0-9][0-9][0-9]'),
);

create table Out_stock
(  prj_num char(8),
   mat_num char(8),
   amount int,
   get_date datetime default getdate(),         /* get_date属性的默认值为系统时间 */
   department char(20),
   primary key(prj_num,mat_num),
                                               /* 主键由两个属性构成，必须作为表格完整性约束*/
   foreign key(prj_num) references Salvaging(prj_num),
                                               /* 表格完整性约束条件，prj_num是外键，被参照表是Salvaging*/
   foreign key(mat_num) references Stock(mat_num),
                                               /* 表格完整性约束条件，mat_num是外键，被参照表是Stock*/
);

 

结果视图

dbo.Salvaging

 

dbo.Out_stock

 

dbo.Stock