Node 1 references a non-existing node 0 as its parent. Try with:
n.parent_id = None -- Ronan Amicel Le 19 avr. 2011 à 16:32, Aviv Giladi <[email protected]> a écrit : > Hey guys, > I am playing around with SQLAlchemy (over Pylons) and encountering a > strange problem. I am using the adjacency list relationship concept to > represent nodes and their parents in a single table. I copied exactly > this code from the examples: > > class Node(Base): > __tablename__ = 'nodes' > id = Column(Integer, primary_key=True) > parent_id = Column(Integer, ForeignKey('nodes.id')) > data = Column(Unicode(50)) > > children = relationship('Node', > cascade="all", > backref=backref("parent", remote_side='Node.id'), > # tried with and without this: > collection_class=attribute_mapped_collection('data'), > ) > > My test is basically adding two nodes, like so: > > n = Node() > n.id = 1 > n.parent_id = 0 > n.data = 'parent' > n2 = Node() > n2.id = 2 > n2.parent_id = 1 > n2.data = 'child' > Session.add(n) > Session.add(n2) > Session.commit() > > When I run my test, I get the following exception raised from > connections.py: > sqlalchemy.exc.IntegrityError: (IntegrityError) (1452, 'Cannot add or > update a child row: a foreign key constraint fails (`db`.`nodes`, > CONSTRAINT `nodes_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `nodes` > (`id`))') 'INSERT INTO nodes (id, parent_id, data) VALUES (%s, %s, > %s)' (1, 0, 'parent') > > Please, what am I missing here? > > Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "pylons-discuss" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/pylons-discuss?hl=en. > -- You received this message because you are subscribed to the Google Groups "pylons-discuss" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/pylons-discuss?hl=en.
