大约有 3,551 项符合查询结果(耗时:0.0272秒) [XML]

https://stackoverflow.com/ques... 

Multiple INSERT statements vs. single INSERT with multiple VALUES

... Addition: SQL Server 2012 shows some improved performance in this area but doesn't seem to tackle the specific issues noted below. This should apparently be fixed in the next major version after SQL Server 2012! Your plan shows t...
https://stackoverflow.com/ques... 

What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phon

What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone. 5 Answers ...
https://stackoverflow.com/ques... 

How to detect if a stored procedure already exists

...f you drop it you know you have to re-add the permissions. If you ran this sql you would not know whether the sproc had the correct permissions or not as you wouldn't know if you had created it or altered it. – Liazy Jan 25 '13 at 12:03 ...
https://stackoverflow.com/ques... 

Profiling Django

...I didn't realize how much slower the Debug Toolbar made things process. My sql queries were small (30ms) but cpu time was very high (800ms). Another page i was tuning had sql times of 300ms, and cpu time of 8000ms - so i kept trying to find the source of the problem. Turning Django Toolbar off sped ...
https://stackoverflow.com/ques... 

SQL Server insert if not exists best practice

... I definitely believe this is the right way to go, giving SQL Server the best possible hints for optimizing, in contrast to the sub query approach. – Mads Nielsen Mar 3 '16 at 20:48 ...
https://stackoverflow.com/ques... 

SCOPE_IDENTITY() for GUIDs?

...s an equivalent of SCOPE_IDENTITY() when using GUIDs as a primary key in SQL Server? 5 Answers ...
https://stackoverflow.com/ques... 

ALTER DATABASE failed because a lock could not be placed on database

...t the problem has occurred elsewhere. http://www.geakeit.co.uk/2010/12/11/sql-take-offline-fails-alter-database-failed-because-a-lock-could-not-error-5061/ share | improve this answer | ...
https://stackoverflow.com/ques... 

What are the best practices for using a GUID as a primary key, specifically regarding performance?

...ly recommend not to do is use the GUID column as the clustering key, which SQL Server does by default, unless you specifically tell it not to. You really need to keep two issues apart: the primary key is a logical construct - one of the candidate keys that uniquely and reliably identifies every r...
https://www.tsingfun.com/it/opensource/451.html 

Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...

...原理: 当用户通过extmail登陆时,首先extmail先去通过mysql进行虚拟用户认证,当认证通过时,postfix通过Cyrus-SASL这个函数库,这个认证框架,结合Courier-authlib对发信人进行认证,通过检索Mysql数据库中的数据来进行认证,以此来...
https://stackoverflow.com/ques... 

How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?

...ery frequently asked question here is how to do an upsert, which is what MySQL calls INSERT ... ON DUPLICATE UPDATE and the standard supports as part of the MERGE operation. ...