I am getting a new error with 0.5.3, I've tried to work around it but
can't seem to find the
right magic.
Can't determine relation direction for relationship 'Taggable.owner' -
foreign key columns are present in both the parent and the child's
mapped tables. Specify 'foreign_keys' argument.
An example code is below (works in 0.5.2, breaks in 0.5.3)
Changing the 'owner' property to work with the user table removes the
error,
but the owner is never actually set in the DB...
#'owner' : relation (User,
# primaryjoin=(taggable.c.owner_id ==
users.c.id),
# foreign_keys=[users.c.id],
# uselist=False,
# ),
from sqlalchemy import Table, Column, Integer, String, MetaData,
ForeignKey, UnicodeText
from sqlalchemy.orm import mapper,relation, sessionmaker
metadata = MetaData()
taggable = Table('taggable', metadata,
Column('id', Integer, primary_key=True),
Column('type', UnicodeText),
Column('owner_id', Integer, ForeignKey
('taggable.id')),
)
users = Table ('users', metadata,
Column('id', Integer, ForeignKey('taggable.id'),
primary_key=True),
Column('user_name', UnicodeText),
)
tags = Table ('tags', metadata,
Column('id', Integer, ForeignKey('taggable.id'),
primary_key=True),
Column('parent_id', Integer, ForeignKey('taggable.id')),
Column('tag', UnicodeText)
)
images= Table ('images', metadata,
Column('id', Integer, ForeignKey('taggable.id'),
primary_key=True),
Column('src', UnicodeText),
)
class Taggable(object):
pass
class Image(Taggable):
def __init__(self):
self.type="image"
class Tag(Taggable):
def __init__(self, v = None):
self.type="tag"
self.tag = v
class User(Taggable):
def __init__(self):
self.type="user"
mapper( Taggable, taggable, properties = {
'owner' : relation (User,
primaryjoin=(taggable.c.owner_id ==
taggable.c.id),
# foreign_keys=[taggable.c.id],
uselist=False,
),
'tags' : relation(Tag, lazy=True, cascade="all, delete-orphan",
primaryjoin= (tags.c.parent_id==taggable.c.id))
}
)
mapper(Image, images, inherits=Taggable,
inherit_condition=(images.c.id == taggable.c.id),
)
mapper(Tag, tags, inherits=Taggable,
inherit_condition=(tags.c.id == taggable.c.id),
)
mapper(User, users, inherits=Taggable,
inherit_condition=(users.c.id == taggable.c.id),
)
from sqlalchemy import create_engine
engine = create_engine('sqlite:///:memory:', echo=True)
metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()
k = User()
k.owner = k
k.user_name ="k"
session.add(k)
i = Image()
i.owner = k
i.src = "someplace"
session.add(i)
tags = [ Tag("t%d" % x ) for x in range(2) ]
for t in tags:
t.owner = k
i.tags = tags
session.flush()
session.commit()
#print k.id
#print i.id, i.owner_id
#print "TAGS", i.tags
i = session.query(Image).all() [0]
print "IMAGE", i.id, i.owner
i.tags = []
session.commit()
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