leader/follower is often used in this case.
On 12/09/2016 10:33 AM, b...@sfi.ca wrote:
Thanks Mike for the quick reply.
I have changed the code so it uses backref on one side. The models now
get created w/o error. I haven't actually tested using the relationship
but I'm sure it's fine now.
For anyone else with this problem, here's the 'fixed' code. I didn't
change the Artifact_Reference table, it's the same as posted above. I'm
not keen on the naming master/slave.. maybe primary/secondary would be
better.. It's not exactly Parent/Child.. heh.
|
class Artifact_Relation(Base):
__tablename__ = 'artifact_relation'
master_artifact_id = Column(
Integer,
ForeignKey('artifact.id', name='artifact_relation_master_id_fk',
ondelete="cascade", onupdate="cascade"),
primary_key=True,
nullable=False
)
slave_artifact_id = Column(
Integer,
ForeignKey('artifact.id', name='artifact_relation_slave_id_fk',
ondelete="cascade", onupdate="cascade"),
primary_key=True,
nullable=False
)
relationship_type = Column(String(24), nullable=False)
slave = relationship("Artifact", backref=backref("masters"),
foreign_keys=[slave_artifact_id])
master = relationship("Artifact", backref=backref("slaves"),
foreign_keys=[master_artifact_id])
class Artifact(Base):
"Artifact"
__tablename__ = 'artifact'
id = Column('id', Integer, primary_key=True)
artifact_type = Column('artifact_type', String(16), nullable=False)
__mapper_args__ = {
'polymorphic_on': artifact_type
}
artifact_references = relationship(
'Artifact_Reference',
back_populates='artifact',
cascade="all, delete-orphan",
passive_deletes=True
)
|
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http://www.sqlalchemy.org/
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Example. See http://stackoverflow.com/help/mcve for a full description.
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