大约有 7,000 项符合查询结果（耗时：0.0365秒） [XML]
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 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...
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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Comparing two dictionaries and checking how many (key, value) pairs are equal
...t(json.dumps(diff, indent=4))
Output
{
"values_changed": {
"root['a']": {
"new_value": 2,
"old_value": 1
},
"root['nested']['b']": {
"new_value": 2,
"old_value": 1
}
}
}
Note about pretty-printing the result...
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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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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Making macOS Installer Packages which are Developer ID ready
...e/DerivedData/.../InstallationBuildProductsLocation
$ pkgbuild --analyze --root ./HelloWorld.app HelloWorldAppComponents.plist
$ pkgbuild --analyze --root ./Helper.app HelperAppComponents.plist
This give us the component-plist, you find the value description in the "Component Property List" sectio...
detect key press in python?
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keyboard apparently requires root in linux :/
– Inaimathi
Nov 14 '17 at 16:05
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How to use unicode characters in Windows command line?
...se this small Batch-Script for the most common code pages.
@ECHO off
SET ROOT_KEY="HKEY_CURRENT_USER"
FOR /f "skip=2 tokens=3" %%i in ('reg query HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage /v OEMCP') do set OEMCP=%%i
ECHO System default values:
ECHO.
ECHO ...................
How to create a new (and empty!) “root” branch?
I would like to define a new "root" branch in this git repository. By "root" branch I mean a branch that is entirely independent of all the other branches in the repository 1 .
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