SQL Server触发器和事务用法示例

时间:2020-12-16 ajunfly 人气:0

这篇文章主要介绍了SQL Server触发器和事务用法,结合实例形式分析了SQL Server触发器、事务、存储过程、游标、视图等的相关定义与使用方法,需要的朋友可以参考下

本文实例讲述了SQL Server触发器和事务用法。分享给大家供大家参考，具体如下：

新增和删除触发器

alter trigger tri_TC on t_c
  for INSERT,delete
as
begin
  set XACT_ABORT ON
  declare @INSERTCOUNT int;
  declare @DELETECOUNT int;
  declare @UPDATECOUNT int;
  set @INSERTCOUNT = (select COUNT(*) from inserted);
  set @DELETECOUNT = (select COUNT(*) from deleted);
  set @UPDATECOUNT = ()
  if(@INSERTCOUNT > 0)
  begin
   insert into t_c2 select * from inserted;
  end
  else if(@DELETECOUNT > 0)
  begin
   delete t_c2 where exists(select temp.cid from deleted temp where temp.cid=t_c2.cid);
  end
end

更新触发器和事务

事务主要用在数据的保护，在多表更新时，事务保存所有事务下的更新语句就不会提交，数据也就不能更新成功

alter trigger tri_TC_Update on t_c
  for update
as
begin
  declare @delcount int;
  set @delcount = (select count(*) from deleted);
  if(@delcount > 0)
  begin
   begin transaction triUpdate --定义事务
   declare @cname varchar(100);
   select @cname = cname from inserted; --保存更新后的内容
   update t_c2 set cname = @cname where cid = (select cid from deleted); --更新
   if (@@error <> 0)
   begin
    rollback transaction triUpdate; --事务回滚
   end
   else
   begin
    commit transaction triUpdate;  --事务提交
   end
  end
end

存储过程

if(exists(select name from sysobjects s where s.name='pro_fun' and s.type='p'))
  drop procedure pro_fun
go
  create procedure pro_fun
as
  select * from table
go
exec pro_fun

游标

declare @qybh varchar(10)
declare cur cursor for
  select distinct qybh from PJ_EnterpriseInput
open cur
fetch next from cur into @qybh
while @@fetch_status = 0
 begin
  print(@qybh)
  fetch next from cur into @qybh
 end
close cur
deallocate cur

视图

alter view CreateView
as
 select qybh from CreateView
go

定义方法

alter function funName(@str1 varchar(10),@str2 varchar(10))
returns varchar(10)
as
begin
  declare @returnStr varchar(10)
  set @returnStr = 'false'
  if(@str1 > @str2)
    set @returnStr = 'true'
  return @returnStr
end
select dbo.funName(... , ...)

定义表变量

declare @qybhTable table (id varchar(32),qybh varchar(30))
insert into @qybhTable
select id,qybh from PJ_EnterpriseInput
select * from @qybhTable

case when then 条件统计时的使用

select
sum(case when z.watchName='注册监理工程师' then 1 else 0 end),
sum(case when z.watchName='xinza' then 1 else 0 end),
sum(case when z.watchName='监理员' then 1 else 0 end)
from zu_corjl z
right join zu_corjltemp t on t.corID=z.corID

希望本文所述对大家SQL Server数据库程序设计有所帮助。

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