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What's the difference between NOT EXISTS vs. NOT IN vs. LEFT JOIN WHERE IS NULL?
... NULL is less efficient
In PostgreSQL, NOT IN is less efficient
In Oracle, all three methods are the same.
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OAuth 2.0: Benefits and use cases — why?
... 1 is that it requires both the server and clients to sort and sign identically. This is fiddly code and either it's right or you get 401 Unauthorized with little help. This increases the barrier to writing a client.
By requiring the authorization request to run over SSL, OAuth 2.0 removes the need...
Do you have to put Task.Run in a method to make it async?
... numbers for the sake of this example, granted, it's no processing time at all, it's just a matter of formulating an example here.
...
How exactly do Django content types work?
I'm really having a difficult time grasping the concept of Django's content types. It feels very hackish and, ultimately, against how Python tends to do things. That being said, if I'm going to use Django then I have to work within the confines of the framework.
...
What is Android keystore file, and what is it used for?
... going to use "push data" in your app!
– KapteinMarshall
Sep 4 '13 at 9:43
Is Keystore machine specific ? Or we can u...
Uninstall old versions of Ruby gems
...
# remove all old versions of the gem
gem cleanup rjb
# choose which ones you want to remove
gem uninstall rjb
# remove version 1.1.9 only
gem uninstall rjb --version 1.1.9
# remove all versions less than 1.3.4
gem uninstall rjb --v...
How to run a background task in a servlet based web application?
... your job here which should run every 5 seconds.
}
}
Yes, that's really all. The container will automatically pickup and manage it.
EJB unavailable? Use ScheduledExecutorService
If your environment doesn't support EJB (i.e. you're not using not a real Java EE server, but a barebones servle...
What are the differences between vector and list data types in R?
...
Technically lists are vectors, although very few would use that term. "list" is one of several modes, with others being "logical", "character", "numeric", "integer". What you are calling vectors are "atomic vectors" in strict R parl...
How to flatten only some dimensions of a numpy array
...an take -1 as an argument, meaning "total array size divided by product of all other listed dimensions":
e.g. to flatten all but the last dimension:
>>> arr = numpy.zeros((50,100,25))
>>> new_arr = arr.reshape(-1, arr.shape[-1])
>>> new_arr.shape
# (5000, 25)
...
Turning off “created by” stamp when generating files in IntelliJ
...nclude Templates in the popup action search dialog. There should be a tab called Includes on which you will find the Java and ActionScript file types, and the text can simply be removed completely if you like.
But, in more recent versions of IntelliJ things have got quite a bit easier. The first ti...