SQLServer2005 的查询独占模拟
时间:2021-02-20 09:10:31|栏目:|点击: 次
对于应用来说,我并不提倡人为给记录加锁,这样会惹来很多麻烦,况且锁并不能解决所有问题,如果你有这方面好的经验我们可以进一步交流。
对于应用来说,我并不提倡人为给记录加锁,这样会惹来很多麻烦,况且锁并不能解决所有问题,如果你有这方面好的经验我们可以进一步交流。
set nocount on
use tempdb
go
if (object_id ('tb' ) is not null )
drop table tb
go
create table tb (id int identity (1 , 1 ), name varchar (10 ), tag int default 0 )
insert into tb (name ) select 'a'
insert into tb (name ) select 'b'
insert into tb (name ) select 'c'
insert into tb (name ) select 'd'
insert into tb (name ) select 'e'
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
set nocount off
/*
id name
----------- ----------
1 a
2 b
id name
----------- ----------
3 c
4 d
id name
----------- ----------
5 e
*/
如果你有更好的建议,我们不妨探讨一下。
对于应用来说,我并不提倡人为给记录加锁,这样会惹来很多麻烦,况且锁并不能解决所有问题,如果你有这方面好的经验我们可以进一步交流。
复制代码 代码如下:
set nocount on
use tempdb
go
if (object_id ('tb' ) is not null )
drop table tb
go
create table tb (id int identity (1 , 1 ), name varchar (10 ), tag int default 0 )
insert into tb (name ) select 'a'
insert into tb (name ) select 'b'
insert into tb (name ) select 'c'
insert into tb (name ) select 'd'
insert into tb (name ) select 'e'
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
update top (2 ) tb with (rowlock , readpast ) set tag = 1 output inserted . id , inserted . name where tag = 0
go
set nocount off
/*
id name
----------- ----------
1 a
2 b
id name
----------- ----------
3 c
4 d
id name
----------- ----------
5 e
*/
如果你有更好的建议,我们不妨探讨一下。
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