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The relationship could not be changed because one or more of the foreign-key properties is non-nulla
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You should delete old child items thisParent.ChildItems one by one manually. Entity Framework doesn't do that for you. It finally cannot decide what you want to do with the old child items - if you want to throw them away or if you want to keep and assign them to other parent enti...
Django: How to manage development and production settings?
..., "shared settings" file), and use DJANGO_SETTINGS_MODULE to control which one to use.
Here's how:
As noted in the Django documentation:
The value of DJANGO_SETTINGS_MODULE should be in Python path syntax, e.g. mysite.settings. Note that the settings module should be on the Python import searc...
What does axis in pandas mean?
... numpy.mean usage when axis is specified explicitly (in numpy.mean, axis==None by default, which computes the mean value over the flattened array) , in which axis=0 along the rows (namely, index in pandas), and axis=1 along the columns. For added clarity, one may choose to specify axis='index' (inst...
Why must a nonlinear activation function be used in a backpropagation neural network? [closed]
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One sentence answer: <<no matter how many layers would behave just like a single perceptron (because linear functions added together just give you a linear function).>>. Nice!
– Autonomous
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Xml configuration versus Annotation based configuration [closed]
...been working on lately it seems to become increasingly important to choose one or the other (XML or Annotation). As projects grow, consistency is very important for maintainability.
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jQuery: $().click(fn) vs. $().bind('click',fn);
....com/a/519455/292408 below for the example. You can of course only bind to one event, e.g. 'click' as well.
– Elijah Lynn
Nov 8 '13 at 16:41
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How do I create a constant in Python?
...attribute, and can contain any value. Declaration is easy Nums = Constants(ONE=1, PI=3.14159, DefaultWidth=100.0), Usage is straightforward print 10 + Nums.PI, attempt to change results in exception Nums.PI = 22 => ValueError(..).
– ToolmakerSteve
Dec 11 '13...
How to find a deleted file in the project commit history?
...-file>
Note the caret symbol (^), which gets the checkout prior to the one identified, because at the moment of <SHA> commit the file is deleted, we need to look at the previous commit to get the deleted file's contents
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C#: how to get first char of a string?
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The difference between this answer and the chosen one is that this solution returns a string, and the other returns a char.
– Loïc Lopes
Sep 6 '17 at 14:51
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Memcached vs. Redis? [closed]
...d at ~225MB. They are similarly efficient in how they store data, but only one is capable of reclaiming it.
Disk I/O dumping: A clear win for redis since it does this by default and has very configurable persistence. Memcached has no mechanisms for dumping to disk without 3rd party tools.
Scaling:...