Django中的查询树模型

Question

How do you usually query comment thread that can be nested?

from django.db import models


class Comment (models.Model):
    # if parent is blank, comment is top level
    parent = models.ForeignKey('Comment',
                           related_name='children',
                           null=True)
    text = models.TextField(blank=True)

    def __repr__(self):
        return self.text


"""
from tree.models import Comment
c1 = Comment(text='c1')
c1.save()
c11 = Comment(text='c11', parent=c1)
c12 = Comment(text='c12', parent=c1)
c11.save()
c12.save()
c111 = Comment(text='c111', parent=c11)
c112 = Comment(text='c112', parent=c11)
c111.save()
c112.save()
c1.children.all() -> return [c111, c112] should return [c111, c112, c11, c12]
"""

In the example above, I created a tree

            c1
     c11          c12
c111   c112

and tried to query the child of c1, but it only returns the immediate child. Do I have to write custom query in my serializer?

Answer 1

Have you consider using Django-treebeard ? It internally does the job of storing the correct indexes of your tree in such a way that it is efficient to query it. I highly recommend it.