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What is Persistence Context?
...erence/en/html/architecture.html
In Java EE, a persistence context is normally accessed via an EntityManager.
http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html
The various states an entity can have and the transitions between these are described below:
http://docs.jboss.or...
Is a view faster than a simple query?
...es.
Update: At least three people have voted me down on this one. With all due respect, I think that they are just wrong; Microsoft's own documentation makes it very clear that Views can improve performance.
First, simple views are expanded in place and so do not directly contribute to performa...
How to swap keys and values in a hash
...;:b, 3=>:c}
BUT...
If you have duplicate values, invert will discard all but the last occurrence of your values (because it will keep replacing new value for that key during iteration). Likewise, key will only return the first match:
{a: 1, b: 2, c: 2}.key(2)
=> :b
{a: 1, b: 2, c: 2}.inv...
What C++ Smart Pointer Implementations are available?
...g limited garbage collection facilities. The first downside being that it calls delete upon destruction making them unacceptable for holding array allocated objects (new[]). It takes ownership of the pointer so two auto pointers shouldn't contain the same object. Assignment will transfer ownership a...
Fatal error: Class 'ZipArchive' not found in
I have a problem that I install 'Archive_Zip 0.1.1' on Linux server, but when I try to run the script to create the zip file it gives the fatal error
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PHP PDO returning single row
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Do you really need to LIMIT 1 all the time though? Knowing that you're selecting a UNIQUE value comes to mind.
– Super Cat
Feb 1 '17 at 3:10
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Should Github be used as a CDN for javascript libraries? [closed]
.... The last one means less total work for everybody, so it's clearly a win all around, and is more likely the more often we (developers) rely on the CDNs to serve our javascript.
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nodeValue vs innerHTML and textContent. How to choose?
...t in firefox until FireFox 45 according to caniuse but is now supported in all major browsers.
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Java 256-bit AES Password-Based Encryption
I need to implement 256 bit AES encryption, but all the examples I have found online use a "KeyGenerator" to generate a 256 bit key, but I would like to use my own passkey. How can I create my own key? I have tried padding it out to 256 bits, but then I get an error saying that the key is too long. ...
Convert NSArray to NSString in Objective-C
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Won't this accomplish the same thing as calling [array description]?
– TechZen
Dec 1 '09 at 20:55
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