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When to add what indexes in a table in Rails
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Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be created automaticall...
How can I check if an argument is defined when starting/calling a batch file?
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The check for whether a commandline argument has been set can be [%1]==[], but, as Dave Costa points out, "%1"=="" will also work.
I also fixed a syntax error in the usage echo to escape the greater-than and less-than signs. In additio...
How do you modify a CSS style in the code behind file for divs in ASP.NET?
I'm trying to modify a CSS style attribute for a div based on the information I get from a database table in the code behind of my aspx page. The following is essentially what I am trying to do, but I get errors.
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Is GridFS fast and reliable enough for production?
I develop a new website and I want to use GridFS as storage for all user uploads, because it offers a lot of advantages compared to a normal filesystem storage.
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What is the difference between task and thread?
...een Thread and Task . I did some sample program(help taken from MSDN) for my own sake of learning with
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Collections.emptyMap() vs new HashMap()
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From Effective Java, Item #43 - "Return empty arrays or collections, not null" demonstrates returning an empty collection and perhaps even demonstrates using these emptyList(), emptySet(), and emptyMap() methods on the Collections class to get an empty collection that also has ...
What does 'super' do in Python?
...ed to write a class that extended Child and a mixin, their code would not work properly.
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Default visibility for C# classes and members (fields, methods, etc.)?
I'm trying to find a reference for the default visibility of various aspects of C#. Class types, fields, methods, enums, etc.
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nginx missing sites-available directory
...having is that I can't seem to find the /etc/nginx/sites-available directory.
3 Answers
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Checking if an Android application is running in the background
...plication by yourself using Activity.onPause, Activity.onResume methods. Store "visibility" status in some other class. Good choices are your own implementation of the Application or a Service (there are also a few variations of this solution if you'd like to check activity visibility from the servi...