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Fastest way to get the first object from a queryset in django?
...eturn None if there aren't any. There are lots of ways to do this which all work. But I'm wondering which is the most performant.
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How do I REALLY reset the Visual Studio window layout?
I had a plugin installed in Visual Studio 2008, and it created some extra dockable windows. I have uninstalled it, and I can't get rid of the windows it created - I close them, but they always come back. They're just empty windows now, since the plugin is no longer present, but nothing I've tried ...
Where does gcc look for C and C++ header files?
...stem header.
If you run gcc in verbose mode on such a source, it will list all the system include locations as it looks for the bogus header.
$ echo "#include <bogus.h>" > t.c; gcc -v t.c; rm t.c
[..]
#include "..." search starts here:
#include <...> search starts here:
/usr/local...
MySQL “NOT IN” query
I wanted to run a simple query to throw up all the rows of Table1 where a principal column value is not present in a column in another table ( Table2 ).
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List All Redis Databases
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Or you can just run the following command and you will see all databases of the Redis instance without firing up redis-cli:
$ redis-cli INFO | grep ^db
db0:keys=1500,expires=2
db1:keys=200000,expires=1
db2:keys=350003,expires=1
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Are duplicate keys allowed in the definition of binary search trees?
...cluded. For example, the example algorithms in the MIT Algorithms book usually present examples without duplicates. It is fairly trivial to implement duplicates (either as a list at the node, or in one particular direction.)
Most (that I've seen) specify left children as <= and right children ...
Is it possible to get all arguments of a function as single object inside that function?
...t an "Object which has a length property of a non-negative Integer, and usually some indexed properties." From the mozilla link: "It is similar to an Array, but does not have any Array properties except length."
– Luke
Aug 7 '17 at 13:09
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How to truncate a foreign key constrained table?
...ata integrity.
Option 1:
Remove constraints
Perform TRUNCATE
Delete manually the rows that now have references to nowhere
Create constraints
Option 2: suggested by user447951 in their answer
SET FOREIGN_KEY_CHECKS = 0;
TRUNCATE table $table_name;
SET FOREIGN_KEY_CHECKS = 1;
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Understanding MongoDB BSON Document size limit
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First off, this actually is being raised in the next version to 8MB or 16MB ... but I think to put this into perspective, Eliot from 10gen (who developed MongoDB) puts it best:
EDIT: The size has been officially 'raised' to 16MB
So, on your...
Tar a directory, but don't store full absolute paths in the archive
...-C works; just for clarification I'll post 2 examples:
creation of a tarball without the full path:
full path /home/testuser/workspace/project/application.war and what we want is just project/application.war so:
tar -cvf output_filename.tar -C /home/testuser/workspace project
Note: there is a ...