大约有 19,000 项符合查询结果（耗时：0.0332秒） [XML]
Does a UNIQUE constraint automatically create an INDEX on the field(s)?
...email, user_id) is enough, you don't need a separate index on email only - MySQL can use leftmost parts of a composite index. There may be some border cases where the size of an index can slow down your queries, but you should not worry about them until you actually run into them.
As for testing in...
Why all the Active Record hate? [closed]
...database itself, tables, relations, even some logic if the DBMS allows it (MySQL is also grown-up now)
A2) very often, there is more than a data store: file system (blobs in database are not always a good decision...), legacy systems (imagine yourself "how" they will be accessed, many varieties pos...
Does Foreign Key improve query performance?
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foreign keys do improve performance, at least in MySQL. Moreover, you're right, the creation of a FK does not create an index; the creation of a FK requires an index
– Félix Gagnon-Grenier
Aug 26 '14 at 17:31
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Unable to execute dex: GC overhead limit exceeded in Eclipse
...art eclipse
The same eclipse.ini file will be located in Eclipse in this root path of eclipse itself like:
C:\Users\username\Downloads\adt-bundle-windows-x86_64-20140702\eclipse\eclipse.ini
The same file will be located in android studio project:-
C:\Users\username\AppData\Local\Android\sdk\to...
AWS ssh access 'Permission denied (publickey)' issue [closed]
...ec2-user instead of ubuntu.
Most EC2 Linux images I've used only have the root user created by default.
See also: http://www.youtube.com/watch?v=WBro0TEAd7g
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How to find corresponding log files folder for a web site?
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It's also shown on the root Sites node, in the listing.
– Josh M.
Feb 3 '17 at 14:53
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Convert xlsx to csv in Linux with command line
... Please beware of the consequences, including the possibility to acquiring root permissions on a multi-user platform
– Interarticle
Aug 1 '13 at 7:42
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Downloading images with node.js [closed]
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@Gofilord its download the image to your root directory.
– dang
Mar 30 '16 at 12:58
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What is this Javascript “require”?
...ich points at this directory. i.e if your node_modules directory is in the root of the project at the same level as your index.html you would write this in your index.html:
<script src="node_modules/ng"></script>
That whole script will now be loaded into the page - so you can access i...
set up device for development (???????????? no permissions)
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I use root to execute command "adb devices" under <android-SDK>/platform-tool/ , I got "No command 'adb' found", why?
– Leem.fin
Feb 9 '12 at 12:11
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