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SQL Server Insert if not exists
...akes no difference whatsoever because it's being used in an EXISTS clause. SQL Server will always optimize it and has been doing it for ages. Since I'm very old I usually write these queries as EXISTS (SELECT 1 FROM...) but it is not needed anymore.
– Loudenvier
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What should every developer know about databases? [closed]
...tent data associated with just one application. Building a database for MySQL, or Access, or SQL Server has become so routine that databases have become almost a routine part of an ordinary application. Sometimes, that initial limited mission gets pushed upward by mission creep, as the real value ...
select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...就行了，这节省了大量的CPU时间。这就是回调机制带来的性能提升。
（2）select，poll每次调用都要把fd集合从用户态往内核态拷贝一次，并且要把current往设备等待队列中挂一次，而epoll只要一次拷贝，而且把current往等待队列上...
Cannot use a CONTAINS or FREETEXT predicate on table or indexed view because it is not full-text ind
I am getting following error in my SQL server 2008 R2 database:
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大单融资后，MOOC去哪儿 - 资讯 - 清泛网 - 专注C/C++及内核技术
...是其必然的发展方向。
“海外的大学已经通过MOOC提供了包括AP课程、本科、硕士、博士等在内的所有教育体系，目前清华大学也已经提供了二学位、MBA和硕士教育的课程学习。”张有明表示，“高等教育在任何国家都是由国家...
SQL Server add auto increment primary key to existing table
...ould recommend to always explicitly specify the seed and increment in your SQL scripts - especially for a larger site. It's just good practice.
– marc_s
Oct 28 '15 at 13:59
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Where can I download english dictionary database in a text format? [closed]
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androidtech/wordnet20 is in SQL format not txt.
– DragonLord
Jun 11 '16 at 22:38
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Convert SQLITE SQL dump file to POSTGRESQL
I've been doing development using SQLITE database with production in POSTGRESQL. I just updated my local database with a huge amount of data and need to transfer a specific table to the production database.
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Nested select statement in SQL Server
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What's the difference between IQueryable and IEnumerable
...t of as "is the 'Age' property > 18".
This allows things like LINQ-to-SQL to exist because they can parse the expression tree and convert it into equivalent SQL. And because the provider doesn't need to execute until the IQueryable is enumerated (it implements IEnumerable<T>, after all)...