I'm using SQLAlchemy's association_proxy to have extensible metadata for my
mapped classes.
So for example I can say:
user.meta[u'foo'] = u'bar'
However when I try to delete an individual item I get an IntegrityError:
users_meta.user_id may not be NULL ...
So likely I'm missing some 'cascade' configuration in my schema setup or so
and I'm glad for any pointers.
I attached a minimal script to reproduce the issue. Thank you very much,
fs
PS: I found
http://docs.sqlalchemy.org/en/rel_0_7/dialects/sqlite.html#sqlite-foreign-keys
but that doesn't seem to make a difference in my case
(sqlite-3.7.13-2.fc18.x86_64).
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from sqlalchemy import Column, ForeignKey, Table, UniqueConstraint, MetaData
from sqlalchemy.ext.associationproxy import association_proxy
from sqlalchemy.types import Unicode, Integer
from sqlalchemy.orm import mapper, relation
from sqlalchemy.orm.collections import attribute_mapped_collection
metadata = MetaData()
users = Table('users', metadata,
Column('id', Integer, autoincrement=True, primary_key=True),
Column('name', Unicode(250), nullable=False),
)
users_meta = Table('users_meta', metadata,
Column('id', Integer, autoincrement=True, primary_key=True),
Column('user_id', Integer,
ForeignKey('users.id', onupdate='CASCADE', ondelete='CASCADE'),
index=True,
nullable=False),
Column('key', Unicode(64), nullable=False),
Column('value', Unicode(250), default=None),
UniqueConstraint('user_id', 'key'),
mysql_engine='InnoDB',
mysql_charset='utf8',
)
class UserMeta(object):
def __init__(self, key, value):
self.key = key
self.value = value
class User(object):
meta = association_proxy('_meta', 'value', creator=UserMeta)
mapper(
User, users,
properties={
'_meta': relation(
UserMeta,
collection_class=attribute_mapped_collection('key'),
passive_deletes=True,
),
},
)
mapper(UserMeta, users_meta)
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
engine = create_engine("sqlite:///:memory:")
metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()
user = User()
user.name = u'foo'
user.meta[u'key'] = u'bar'
session.add(user)
session.commit()
del user.meta[u'key']
session.commit()
