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Update MongoDB field using value of another field
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The best way to do this is in version 4.2+ which allows using of aggregation pipeline in the update document and the updateOne, updateMany or update collection method. Note that the latter has been deprecated in most if not all languages drivers.
MongoDB 4.2+
Version 4.2 ...
SQL Server: Query fast, but slow from procedure
... the quoted answer did not solve the problem for me. The query still ran really slow from a stored procedure.
I found another answer here "Parameter Sniffing", Thanks Omnibuzz. Boils down to using "local Variables" in your stored procedure queries, but read the original for more understanding, it...
Ways to implement data versioning in MongoDB
... approach would be to store diffs. Because the display of these diffs is really a special action, I would put the diffs in a different "history" collection.
I would use the different collection to save memory space. You generally don't want a full history for a simple query. So by keeping the histo...
Find which version of package is installed with pip
..., is it possible to figure out which version of a package is currently installed?
15 Answers
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Can “using” with more than one resource cause a resource leak?
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No.
The compiler will generate a separate finally block for each variable.
The spec (§8.13) says:
When a resource-acquisition takes the form of a
local-variable-declaration, it is possible to acquire multiple
resources of a given type. A using statement of the...
How to obtain the number of CPUs/cores in Linux from the command line?
... Note that both of these will end up counting twice as many cores as actually exist if you're on a system with hyperthreading (e.g, P4, or Core i7).
– duskwuff -inactive-
Jun 26 '11 at 0:04
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How do you delete an ActiveRecord object?
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It's destroy and destroy_all methods, like
user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)
Alternatively you can use delete and delete_all which won't enforce :before_destroy and :after...
What do linkers do?
...converts the source file into object byte code. This byte code (sometimes called object code) is mnemonic instructions that only your computer architecture understands. Traditionally, these files have an .OBJ extension.
After the object file is created, the linker comes into play. More often than ...
Python: reload component Y imported with 'from X import Y'?
... verse (import this from interactive prompt to see the Zen of Python); and all the reasons why namespaces are a honking great idea (immediate local visual clues that the name's being looked up, ease of mocking/injecting in tests, ability to reload, ability for a module to change flexibly by redefini...
Can I have multiple Xcode versions installed?
Is it possible to have more than one version of Xcode installed at the same time?
12 Answers
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