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Should I commit or rollback a read transaction?
...timization points for your app. If you're really curious, you can find the mySQL transaction handling code at bazaar.launchpad.net/~mysql/mysql-server/mysql-6.0/annotate/…
– Mark Brackett
May 21 '10 at 15:05
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How to import multiple .csv files at once?
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+1 seems like producing a single data frame -- the SQL UNION of all CSV files -- is the easiest to work with. Since OP didn't specify whether they want 1 data frame or many data frames, I assumed 1 data frame is best, so I am surprised the accepted answer does not do any of the "...
How to execute a raw update sql with dynamic binding in rails
...d try accessing the underlying connection and using it's methods, e.g. for MySQL:
st = ActiveRecord::Base.connection.raw_connection.prepare("update table set f1=? where f2=? and f3=?")
st.execute(f1, f2, f3)
st.close
I'm not sure if there are other ramifications to doing this (connections left op...
Cannot issue data manipulation statements with executeQuery()
In MySQL I have two tables, tableA and tableB . I am trying to execute two queries:
10 Answers
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What does WISC (stack) mean? [closed]
... for the software/technology bundle/stack representing Linux , Apache , MySQL , PHP . There are a few passing references on the Web that use the acronym WISC to speak of the other (supposedly Microsoft-centric) software/technology bundle/stack in contrast to LAMP. There is, however, no Wikip...
How to remove not null constraint in sql server using query
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Why does this work and not the above accepted answer for mysql ?
– HopeKing
Feb 13 '18 at 8:47
1
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Can I change a column from NOT NULL to NULL without dropping it?
... I tried with alter column and it didn't work with the latest mysql server. I tried with modify column and it worked. Strange...
– Kostas Andrianos
Aug 19 '17 at 15:29
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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...
Why does “_” (underscore) match “-” (hyphen)?
...cluding zero characters).
(From section 3.3.4.7. Pattern Matching in the MySQL documentation.)
If you want to use the underscore in like as a literal, you have to escape it:
select * from a where name like '%taz\_manual%.pdf%';
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update columns values with column of another table based on condition [duplicate]
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it's not working in mysql
– cikatomo
Sep 30 '15 at 19:30
22
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