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from sqlalchemy import *
metadata = MetaData('sqlite:///', echo=True)
class Tree(object):
def __init__(self, name='', father=None):
self.name = name
self.father = father
def __str__(self):
return '<TreeNode: %s>' % self.name
def __repr__(self):
return self.__str__()
table = Table('tree', metadata,
Column('id', Integer, primary_key=True),
Column('name', String(64), nullable=False),
Column('father_id', Integer, ForeignKey('tree.id'), nullable=True))
table.create()
mapper(Tree, table,
properties={
'childs':relation(Tree, remote_side=table.c.father_id, primaryjoin=table.c.father_id==table.c.id, backref=backref('father', remote_side=table.c.id))},
)
root = Tree('root')
child1 = Tree('child1', root)
child2 = Tree('child2', root)
child3 = Tree('child3', child1)
child4 = Tree('child4')
child1.childs.append(child4)
session = create_session()
session.save(root)
session.flush()
print root.childs
print child1.childs
print child2.childs
print child2.father
print child3.father
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