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In Ruby on Rails, what's the difference between DateTime, Timestamp, Time and Date?
...ith Rails and everything to do with whatever database you're using.
Using MySQL as an example (if for no other reason because it's most popular), you have DATE, DATETIME, TIME and TIMESTAMP column data types; just as you have CHAR, VARCHAR, FLOAT and INTEGER.
So, you ask, what's the difference? We...
Java 理论与实践: 线程池与工作队列 - 更多技术 - 清泛网 - 专注C/C++及内核技术
... POP)、通过 JMS 队列或者可能通过轮询数据库。不管请求如何到达,服务器应用程序中经常出现的情况是:单个任务处理的时间很短而请求的数目却是巨大的。
构建服务器应用程序的一个过于简单的模型应该是:每当一个请求...
UCenter实现各系统通信的原理 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...统通信的原理===本文导读===UCenter实现各系统通信的原理如何实现phpcms和discuz的Cookie同步===全文阅读===整合phpcms v9和discuz X3.2实现同步登陆、退出免激活===本文导读===
整合phpcms v9和discuz X3.2实现同步登陆、退出免激活
如何实现php...
Insert into … values ( SELECT … FROM … )
... struggle to remember the correct syntax for the SQL engine of the day ( MySQL , Oracle , SQL Server , Informix , and DB2 ).
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千亿时代 网游走到十字路口 - 资讯 - 清泛网 - 专注C/C++及内核技术
...能再缓的端游还能挺多久?手游作为游戏增长最大驱动力如何面临资本降温和淘汰加速的考验?电视游戏(包括主机游戏等)能不能接过力促增长的枪?虚拟现实是噱头还是真正的行业未来?这是个十字路口。
结构性调整
China...
Include headers when using SELECT INTO OUTFILE?
Is it possible to include the headers somehow when using the MySQL INTO OUTFILE ?
18 Answers
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How to update two tables in one statement in SQL Server 2005?
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probably not related: this won't work on MYSQL because the update syntax for mysql is different. you'd have to go UPDATE Table1 , Table2 SET Table1.LastName = 'DR. XXXXXX' WHERE T1.id = T2.id
– Juan Vilar
Nov 24 '14 at 10:56...
Possible to do a MySQL foreign key to one of two possible tables?
...ut logical XOR is not standard SQL and is not supported by all SQL brands. MySQL has it, but PostgreSQL does not. Oracle has it, but Microsoft does not until 2016. And so on.
– Bill Karwin
Aug 19 '15 at 15:09
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“where 1=1” statement [duplicate]
I saw some people use a statement to query a table in a MySQL database like the following:
10 Answers
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Difference between string and text in rails?
...l is converted into its respective column type in query language.
with MySQL :string is mapped to VARCHAR(255)
- http://guides.rubyonrails.org/migrations.html
:string | VARCHAR | :limit => 1 to 255 (default = 255)
:text | TINYTEXT, TEXT, MEDIUMTEXT, or...