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Best way to select random rows PostgreSQL
...rately few) gaps.
Obviously no or few write operations.
Your ID column has to be indexed! A primary key serves nicely.
The query below does not need a sequential scan of the big table, only an index scan.
First, get estimates for the main query:
SELECT count(*) AS ct -- optional
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What's the point of NSAssert, actually?
I have to ask this, because: The only thing I recognize is, that if the assertion fails, the app crashes. Is that the reason why to use NSAssert? Or what else is the benefit of it? And is it right to put an NSAssert just above any assumption I make in code, like a function that should never receive ...
When should we call System.exit in Java
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System.exit() can be used to run shutdown hooks before the program quits. This is a convenient way to handle shutdown in bigger programs, where all parts of the program can't (and shouldn't) be aware of each other. Then, if someone wants to quit, he c...
How to add a WiX custom action that happens only on uninstall (via MSI)?
I would like to modify an MSI installer (created through WiX ) to delete an entire directory on uninstall.
6 Answers
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Benefit of using Parcelable instead of serializing object
As I understand, Bundle and Parcelable belongs to the way Android performs serialization in. It is used for example in passing data between activities. But I wonder, if there are any benefits in using Parcelable instead of classic serialization in case of saving state of my business objects to...
Android - Handle “Enter” in an EditText
I am wondering if there is a way to handle the user pressing Enter while typing in an EditText , something like the onSubmit HTML event.
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Why do some claim that Java's implementation of generics is bad?
...t compile time, so at execution time you can't tell what type it's "meant" to be
Can't be used for value types (this is a biggie - in .NET a List<byte> really is backed by a byte[] for example, and no boxing is required)
Syntax for calling generic methods sucks (IMO)
Syntax for constraints can...
Limiting floats to two decimal points
I want a to be rounded to 13.95 .
26 Answers
26
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Cleaning up the iPhone simulator
Is there a straightforward way to clean up the directory where xcode deploys an app when building for the iPhone simulator? I have a sqlite database that gets copied into the Documents folder on startup if necessary. The problem is that I might change my schema, but the new database won't get copie...
How to use sessions in an ASP.NET MVC 4 application?
I am new to ASP.NET MVC. I have used PHP before and it was easy to create a session and select user records based on the current session variables.
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