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I"m wondering if it"s possible to define a foreign key in a models.py file in Django that is a reference to a table in another app?
In other words, I have two apps, called cf and profiles, and in cf/models.py I have (amongst other things):
class Movie(models.Model):
title = models.CharField(max_length=255)
and in profiles/models.py I want to have:
class MovieProperty(models.Model):
movie = models.ForeignKey(Movie)
But I can"t get it to work. I"ve tried:
movie = models.ForeignKey(cf.Movie)
and I"ve tried importing cf.Movie at the beginning of models.py, but I always get errors, such as:
NameError: name "User" is not defined
Am I breaking the rules by trying to tie two apps together in this way, or have I just got the syntax wrong?
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Foreign key from one app into another in Django __del__: Questions
How can I make a time delay in Python?
5 answers
I would like to know how to put a time delay in a Python script.
Answer #1
import time
time.sleep(5) # Delays for 5 seconds. You can also use a float value.
Here is another example where something is run approximately once a minute:
import time
while True:
print("This prints once a minute.")
time.sleep(60) # Delay for 1 minute (60 seconds).
Answer #2
You can use the sleep()
function in the time
module. It can take a float argument for sub-second resolution.
from time import sleep
sleep(0.1) # Time in seconds
Foreign key from one app into another in Django __del__: Questions
How to delete a file or folder in Python?
5 answers
How do I delete a file or folder in Python?
Answer #1
os.remove()
removes a file.os.rmdir()
removes an empty directory.shutil.rmtree()
deletes a directory and all its contents.
Path
objects from the Python 3.4+ pathlib
module also expose these instance methods:
pathlib.Path.unlink()
removes a file or symbolic link.pathlib.Path.rmdir()
removes an empty directory.
We hope this article has helped you to resolve the problem. Apart from Foreign key from one app into another in Django, check other __del__-related topics.
Want to excel in Python? See our review of the best Python online courses 2023. If you are interested in Data Science, check also how to learn programming in R.
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Vigrinia | 2023-03-22
Thanks for explaining! I was stuck with Foreign key from one app into another in Django for some hours, finally got it done 🤗. I am just not quite sure it is the best method
Milan | 2023-03-22
File handling is always a bit confusing 😭 Foreign key from one app into another in Django is not the only problem I encountered. I just hope that will not emerge anymore
California | 2023-03-22
re Python module is always a bit confusing 😭 Foreign key from one app into another in Django is not the only problem I encountered. I am just not quite sure it is the best method