SQL事务、存储过程

id 　　name 　　price
1 　　 张三 　　 850.00
2 　　 李四 　　 850.00

--事务
declare @error int
set @error=0;
begin tran
update Bank 
set price-=100
where
id=1
set @error +=@@ERROR

update Bank
set price+=100
where 
id=2
set @error+=@@ERROR


if( @error=0)
begin 
print '转账成功'
commit tran
end
else
begin
print '转账失败'
rollback tran
end
go


select * from Bank



--存储过程

drop proc usp_changemoney
go

create proc usp_changemoney
--参数列表
@ToId int,
@FromId int,
@money decimal(18,2)

as
--SQL代码
declare  @error int 
set @error=0
begin tran
update Bank
set price-=@money
where id=@FromId
set @error+=@@error
update Bank
set price+=@money
where id=@ToId
set @error+=@@error 
if(@error=0)
begin 
--转义
print '成功转账'+cast(@money as nvarchar)+'元'
commit tran
end
else
begin 
print '转账失败'
rollback tran
end
go

--调用存储过程
 exec 存储过程名称   fromId  toId    转帐金额
exec  usp_changemoney 2,1,150






--存储过程-(带输出值)

drop proc usp_changemoney
go

create proc usp_changemoney
--参数列表
@ToId int,
@FromId int,
@money decimal(18,2),
@ToName nvarchar(50) output,
@UnitPrice decimal(18,2)output

as
--SQL代码
declare  @error int 
set @error=0
begin tran
update Bank
set price-=@money
where id=@FromId
set @error+=@@error
update Bank
set price+=@money
where id=@ToId
set @error+=@@error 

select @ToName= name from Bank
where id=@ToId


if(@error=0)
begin 
--                    转义cast
print '成功转账'+cast(@money as nvarchar)+'元'
commit tran
select @UnitPrice= price from Bank
where id=@FromId
end        
else
begin 
print '转账失败'
rollback tran
end
go

--调用存储过程
declare @ToName nvarchar(50) ,@UnitPrice decimal(18,2)
exec  usp_changemoney 2,1,150,@ToName output,@UnitPrice output
print '被转账人:'+@ToName
print '余额'+cast(@UnitPrice as nvarchar(50))


select * from Bank