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Foreign key constraints: When to use ON UPDATE and ON DELETE
...tent database, and that's one of the good reasons to use a database. Especially if you have several applications requesting it (or just one application but with a direct mode and a batch mode using different sources).
With MySQL you do not have advanced constraints like you would have in postgreSQL...
How to create GUID / UUID?
I'm trying to create globally-unique identifiers in JavaScript. I'm not sure what routines are available on all browsers, how "random" and seeded the built-in random number generator is, etc.
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How to import classes defined in __init__.py
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wow, the word "helper" really starts to loose meaning in that example. However, you've shown me what I was looking for.
– scottm
Feb 24 '09 at 21:06
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sqlalchemy: how to join several tables by one query?
...rmissions.document,
).filter(
User.email == 'someemail',
).all()
share
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if A vs if A is not None:
...
The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation ...
When to use setAttribute vs .attribute= in JavaScript?
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This answer is not clear enough...I don't really feel I understand this yet.
– temporary_user_name
Oct 24 '13 at 21:48
1
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how to break the _.each function in underscore.js
...t provide to escape the loop (other than throwing an exception).
However, all hope is not lost! You can use the Array.every method. :)
From that link:
every executes the provided callback function once for each element present in the array until it finds one where callback returns a false valu...
What it the significance of the Javascript constructor property?
...the constructor property is used in a few places. However, I think the overall gist still applies. Thanks to T. J. Crowder for pointing that out in the comments, and please read his answer for a fuller picture of the current situation.
Original answer
The constructor property makes absolutely no pra...
Best practice for Python assert
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To be able to automatically throw an error when x become less than zero throughout the function. You can use class descriptors. Here is an example:
class LessThanZeroException(Exception):
pass
class variable(object):
def __init__(self, va...
Pandas selecting by label sometimes return Series, sometimes returns DataFrame
...answered Dec 4 '13 at 19:36
Dan AllanDan Allan
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