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When to add what indexes in a table in Rails
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Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be created aut...
Why covariance and contravariance do not support value type
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Basically, variance applies when the CLR can ensure that it doesn't need to make any representational change to the values. References all look the same - so you can use an IEnumerable<string> as an IEnumerable<object>...
Create RegExps on the fly using string variables
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With string literals this is easy enough.
Not really! The example only replaces the first occurrence of string_to_replace. More commonly you want to replace all occurrences, in which case, you have to convert the string into a global (/.../g) RegExp. You can do this from a...
How do you suppress output in IPython Notebook?
...nly want to suppress output from particular lines of code in the cell, not all lines. Thanks
– Confounded
Nov 15 '19 at 11:15
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How to configure MongoDB Java driver MongoOptions for production use?
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Updated to 2.9 :
autoConnectRetry simply means the driver will automatically attempt to reconnect to the server(s) after unexpected disconnects. In production environments you usually want this set to true.
connectionsPerHost are the amount of physical connections a single Mongo instance (it's si...
What exactly do “u” and “r” string flags do, and what are raw string literals?
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There's not really any "raw string"; there are raw string literals, which are exactly the string literals marked by an 'r' before the opening quote.
A "raw string literal" is a slightly different syntax for a string literal, in which a ba...
Push git commits & tags simultaneously
...h . Pushing tags should be a conscious choice since you don't want accidentally push one. That's fine. But is there a way to push both together? (Aside from git push && git push --tags .)
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Best way to structure a tkinter application? [closed]
The following is the overall structure of my typical python tkinter program.
7 Answers
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Can I make fast forwarding be off by default in git?
I can't really ever think of a time when I would use git merge rather than git rebase and not want to have a commit show up. Is there any way to configure git to have fast forwarding off by default? The fact that there's an --ff option would seem to imply that there's a way, but I can't se...
SQLAlchemy: What's the difference between flush() and commit()?
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A Session object is basically an ongoing transaction of changes to a database (update, insert, delete). These operations aren't persisted to the database until they are committed (if your program aborts for some reason in mid-session transaction, any...