Sqlserver事务备份和还原实例

 create database mydb
 use mydb
 go
 create table account(
     id varchar(16),
     name varchar(16),
     balance float
 )
 go
 select * from account

 insert into account(id, name, balance) values('', 'liyong', 300)
 insert into account(id, name, balance) values('', 'mali', 400)
 --insert into account(id, name, balance) values('620009', 'chenying', 800)
 insert into account(id, name, balance) values('', 'chenying', 800)
 --delete from account where id = '620009'
 go
 update account set balance = balance - 1000 where id = ''
 update account set balance = balance + 1000 where id = ''
 --消息 547，级别 16，状态 0，第 1 行
 --UPDATE 语句与 CHECK 约束"CK_Blance"冲突。该冲突发生于数据库"mydb"，表"dbo.account", column 'balance'。
 --语句已终止。

 go
 --alter table account
 --alter COlumn balance int
 go
 alter table account
 add constraint CK_Blance check(balance >= 0)
 go
 alter table account
 drop constraint CK_Blance
 --定一个事务
 --从liyong扣钱往mali加钱
 begin transaction
 update account set balance = balance - 1000 where id = ''
 if((select balance output from account where id = '') < 0)
 begin
 PRINT('余额不足！');
 ROLLBACK;
 end
 else
 begin
     update account set balance = balance + 1000 where id = ''
     commit;
     PRINT('转账成功！');
 end
 go
 sp_help
 --备份设备
 sp_addumpdevice 'disk', 'xk_bak' ,'d:\xk_bak'
 --备份数据库
 backup database mydb
 to xk_bak
 --还原数据库
 restore database mydb from disk = 'd:\xk_bak'
 with replace; --覆盖