Many-to-many self-referential relationship in sqlalchemy

Question

I\'m trying to make a self-referential many-to-many relationship (it means that Line can have many parent lines and many child lines) in sqlalchemy like this:

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Answer 1

You should just need:

prev_lines = relationship(
    Association,
    backref="next_lines",
    primaryjoin=id==Association.prev_id)

Since this specifies the next_lines back reference there is no need to have a next_lines relationship.

You can also do this using the remote_side parameter to a relationship: http://www.sqlalchemy.org/trac/browser/examples/adjacency_list/adjacency_list.py