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How important is the order of columns in indexes?
... 3, the optimizer wouldn't even use the index, because it's not helpful at all in narrowing down the result sets. Anytime you're in a query, narrowing down the number of results to deal with before the next step means better performance.
Since the index is also stored this way, there's no backtrac...
Math.random() explanation
This is a pretty simple Java (though probably applicable to all programming) question:
5 Answers
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How to get text box value in JavaScript
... name. So you could either use getElementsByName() method to get a list of all elements with this name:
var jobValue = document.getElementsByName('txtJob')[0].value // first element in DOM (index 0) with name="txtJob"
Or you assign an ID to the element:
<input type="text" name="txtJob" id="...
Reset push notification settings for app
I am developing an app with push notifications. To check all possible ways of user interaction, I'd like to test my app when a user declines to have push notifications enabled for my app during the first start.
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Mixing C# & VB In The Same Project
...No, you can't. An assembly/project (each project compiles to 1 assembly usually) has to be one language. However, you can use multiple assemblies, and each can be coded in a different language because they are all compiled to CIL.
It compiled fine and didn't complain because a VB.NET project will on...
Why implement interface explicitly?
...tance, if you implement both IComparable<T> and IComparable it is usually nicer to hide the IComparable overload to not give people the impression that you can compare objects of different types. Similarly, some interfaces are not CLS-compliant, like IConvertible, so if you don't explicitly im...
How to get correct timestamp in C#
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var timestamp = DateTime.Now.ToFileTime();
//output: 132260149842749745
This is an alternative way to individuate distinct transactions. It's not unix time, but windows filetime.
From the docs:
A Windows file time is a 64-bit value that represents the number of 100-
nanosec...
Best way to extract a subvector from a vector?
Suppose I have a std::vector (let's call it myVec ) of size N . What's the simplest way to construct a new vector consisting of a copy of elements X through Y, where 0
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How to compare software version number using js? (only number)
...from the two arrays; if the parts are not equal we know which version is smaller.
There are a few of important details to keep in mind:
How should the parts in each pair be compared? The question wants to compare numerically, but what if we have version strings that are not made up of just digits...
Generate 'n' unique random numbers within a range [duplicate]
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We, could instead of enclosing the random.sample() call inside the try...except block, check if the size of the sample (3 above) is smaller or equal (<=) than the size of the population (range(1, 2) above).
– Hakim
Mar 11 '17 at 19:42
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