[Fixed]-Making a tree structure in django models?

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30👍

✅

ManyToOneRel is an internal implementation class, it’s not for use in your models.

But why do you think you need it anyway? As the documentation explains in detail, when you define a ForeignKey, you automatically get a reverse relation. So in your case, if you define parent then you automatically get self.foomodel_set already: and you can make it even more explicit by using the related_name parameter:

parent = models.ForeignKey('self', blank=True, null=True, related_name='children')

Note that if you’re planning on doing complicated things with trees, you probably want to be using the django-mptt library.

👤Daniel Roseman

3👍

class FooModel(models.Model)
    parent = models.ForeignKey('self', blank=True, null=True, related_name='children')


FooModel.objects.get(pk=1).children.all()

If you wish to cache use whatever you want: caching of query somewhere, store all children in parent as a flat list of pks, but don’t forget to handle new entities to update this list. ManyToOneRel is for internal needs of django moreover it isn’t an instance of Field class.

👤simplylizz

0👍

I could not find the documentation for ManyToOneRel so I looked up the code for it:

def __init__(self, to, field_name, related_name=None, limit_choices_to=None,
        parent_link=False, on_delete=None):

As you can see, there is no blank argument.

👤Facundo Casco

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