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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
The "N+1 selects problem" is generally stated as a problem in Object-Relational mapping (ORM) discussions, and I understand that it has something to do with having to make a lot of database queries for something that seems simple in the object world.
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How to view corresponding SQL query of the Django ORM's queryset?
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You also can use python logging to log all queries generated by Django. Just add this to your settings file.
LOGGING = {
'disable_existing_loggers': False,
'version': 1,
'handlers': {
'console': {
# logging handler that outputs log...
Get current directory name (without full path) in a Bash script
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No need for basename, and especially no need for a subshell running pwd (which adds an extra, and expensive, fork operation); the shell can do this internally using parameter expansion:
result=${PWD##*/} # to assign to a variable
printf '%s\n' "$...
Iterating over all the keys of a map
Is there a way to get a list of all the keys in a Go language map? The number of elements is given by len() , but if I have a map like:
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C# delete a folder and all files and folders within that folder
I'm trying to delete a folder and all files and folders within that folder, I'm using the code below and I get the error Folder is not empty , any suggestions on what I can do?
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How to remove and clear all localStorage data [duplicate]
I need to clear all data i set into localStorage . By this, I mean completely reset localStorage to null when users remove their accounts.
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List all files in one directory PHP [duplicate]
What would be the best way to list all the files in one directory with PHP? Is there a $_SERVER function to do this? I would like to list all the files in the usernames/ directory and loop over that result with a link, so that I can just click the hyperlink of the filename to get there. Thanks!
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Deleting all rows from Cassandra cql table [duplicate]
Is there a command to all the rows present in a cql table in cassandra like the one in sql?
1 Answer
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ERROR 1130 (HY000): Host '' is not allowed to connect to this MySQL server [duplicate]
...vileges:
CREATE USER 'root'@'ip_address' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'root'@'ip_address';
If you see %, well then, there's another problem altogether as that is "any remote source". If however you do want any/all systems to connect via root, use the % wildcard to gra...
How to re-create database for Entity Framework?
...ed, if so, right click and delete.
2 )Go to Solution Explorer, click show All Files icon.
3) Go to App_Data, right click and delete all ".mdf" files for this project.
4) Delete Migrations folder by right click and delete.
5) Go to SQL Server Management Studio, make sure the DB for this project i...