sql事务

--事务
create table bank
(
	cId char(4) primary key,
	balance money,			--余额
)

alter table bank
add constraint CH_balance check(balance >=10)

go
--delete from bank
insert into bank values('0001',1000)
insert into bank values('0002',10)

--
update bank set balance = balance - 1000 where cid='0001'
update bank set balance = balance + 1000 where cId = '0002'

select * from bank


--事务
declare @sumError int
set @sumError = 0
begin tran  --transaction
	update bank set balance = balance + 1000 where cId = '0002'
	set @sumError = @sumError + @@error
	update bank set balance = balance - 1000 where cid='0001'
	set @sumError = @sumError + @@error
--事务执行成功 提交事务
if(@sumError = 0)
	commit tran
--事务执行失败，回滚
else
	rollback tran

select @sumError