一元关系 flask sqlalchemy

Question

I have a model that I created to store users comments, and because of the nature of comments sections in apps I tried to create my model it in a way such that comments can be under other comments, so I tried to use a unary relationship on the comments model

class Comments(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    comment = db.Column(db.Text, nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False)
    user = db.relationship("User", backref=db.backref("comment", lazy=True))
    meme_id = db.Column(db.Integer, db.ForeignKey("memedata.meme_id"), nullable=False)
    meme = db.relationship("MemeData", backref=db.backref("comment"), lazy=True)
    parent_comment_id = db.Column(db.Integer, db.ForeignKey("comments.id"), nullable=True)
    parent_comment = db.relationship("Comments")

where the parent_comment is a recursive relationship to the model and parent_comment_id is the id of the parent comment. My problem is it doesn't work how I expect it to work.

Basically if the comment has no parent comment (not under any comment) then I pass in Null but when I try to store a comment that has a parent comment (under another comment), it overwrites the parent_comment_id for the PARENT COMMENT to that of the child comment and leaves the CHILD COMMENT parent_comment_id as NULL

Example, we have an initial comment in the database that has no comment under it

id | comment | user_id | meme_id | parent_comment_id
1  | blah... |     1   |     3   |        NULL   

assuming I want to store a comment under this I would do something like

parent=Comments.query.get(1)

comment = Comments(
                comment="another comment",
                user=user,
                meme=meme,
                parent_comment=[parent]
            )

Now what I would expect is...

id | comment     | user_id | meme_id | parent_comment_id
1  | blah...     |     1   |     3   |        NULL  
2  | another...  |     5   |     3   |         1

...however what I get is

id | comment     | user_id | meme_id | parent_comment_id
1  | blah...     |     1   |     3   |        2
2  | another...  |     5   |     3   |       NULL

I would appreciate any comment or method on how I can get my desired result

Answer 1

You specified

    parent_comment=[parent]

It looks like what you want is just an integer:

    parent_comment=parent.id