django models cyclic import-CodePudding

I have read some relevant posts on the issue on mutual imports (circular). I am working on a django app, here's how I run to an issue:

I have two apps, first one articles, second one tags

my article model have a many to many field, to indicate relevant tags:

articles/models.py

from django.db import models
from tags.models import Tag

class Article(models.Model):
    tags = models.ManyToManyField(Tag)

however, in my tags app, I also need to import Article model to achieve the methods:

tags/models.py

from django.db import models
from articles.models import Article

# Create your models here.
class Tag(models.Model):
    title = models.CharField(max_length=100)
    content = models.CharField(max_length=255)

    def getAritcleLength():
        pass

    def getQuestionLength():
        pass

I usually use a module to combine those class definitions, normally won't run into issue according to method resolution order. However, in django the workflow we need to put classes into separated folders, I will be so glad for any suggestion.

CodePudding user response：

Try to delete this string

from articles.models import Article

CodePudding user response：

Don't import the Tag model in the Article model, but use the string reference of the class instead.

# articles/models.py

from django.db import models


class Article(models.Model):
    tags = models.ManyToManyField('Tag')    OR: you can use app_name.model_name format as well

Another way is to use Django's method to get the model from a string and then use that variable in place for the model reference. Django: Get model from string?