Hi
Is it possible two have a one-to-many or many-to-many relationship between
two models which they are exist in two different databases?
I have two oracle dbs on two different machines on lan. so i've created two
engines like:
main_engine = create_engine("oracle://user:pass@ip1/sid")
entry_engine = create_engine("oracle://user:pass@ip2/sid")
Then i've created two different bases for my models and a session:
meta_data = MetaData()
DBSession =
scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
MainBase = declarative_base(cls=ModelBase, metadata=meta_data)
EntryBase = declarative_base(cls=ModelBase, metadata=meta_data)
MainBase.metadata.bind = main_engine
EntryBase.metadata.bind = entry_engine
And let's say i have two simple models like:
class WeatherStation(MainBase):
__tablename__ = "weather_stations"
master_code = Column(NUMBER(10), primary_key=True)
name = Column(String(50), index=True)
evaporation_data = relationship("EvaprationData", backref="station")
and the other one:
class EvaporationData(Base):
__tablename__ = "evaporations_data"
id = Column(NUMBER(30), Sequence("evaporation_data_eid_seq"),
primary_key=True)
station_code = Column(NUMBER(10, 0),
ForeignKey("weather_stations.master_code"))
* each classes defined in separate files models folder.
Now if i comment out the relationships queries works fine. but with
relationships between my models, i've got errors like:
failed to locate a name ("name 'EvaporationData' is not defined"). If this
is a class name, consider adding this relationship() to the <class
'measurement.models.weather_station.WeatherStation'> class after both
dependent classes have been defined.
So is there any solution?
Thank.
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