On 5/8/15 2:41 PM, Carlus wrote:
Hello,
Sorry I couldnt find info about in google neither in the documentation,
I have a model structure like this one:
class Person(Base):
__tablename__ ='person' id = Column(Integer, primary_key=True,
nullable=False)
person_name = Column(String, nullable=False)
accommodation_id = Column(Integer, ForeignKey("accommodation.id"))
accommodation = relationship("Accommodation", backref="people")
def __init__(self, person_name):
self.person_name = person_name
class Accommodation(Base):
__tablename__ ='accommodation' __mapper_args__ =
{'polymorphic_identity':'accommodation',
'polymorphic_on':'accommodation_type'}id = Column(Integer, primary_key=True)
accommodation_type = Column(String(32))
address = Column(String)
class Hotel(Accommodation):
__tablename__ ='hotel' __mapper_args__ = {'polymorphic_identity':'hotel'
}id = Column(Integer, ForeignKey('accommodation.id'), primary_key=True)
hotel_name = Column(String)
def __init__(self, name, address):
self.hotel_name = name
self.address = address
class Apartment(Accommodation):
__tablename__ ='apartment' __mapper_args__ =
{'polymorphic_identity':'apartment' }id = Column(Integer,
ForeignKey('accommodation.id'), primary_key=True)
apartm_name = Column(String)
def __init__(self, name, address):
self.apartm_name = name
self.address = address
Where each Person is associate to some accommodation (thanks to
polymorphic can be Hotel or Apartment), each accommodation can have
more than one Person.
Im having problems when I try to update some record in the table
accommodation, mainly when for example updating the accomodation_type
(an Apartment became into a Hotel, where would get new records in
Hotel and would delete any info from the record in Apartment and
keeping the same id, address, and relationship with People.
I'm not sure what angle you are coming from. Did you want to emit an
UPDATE for accomodation_type? That would be awkward; it means a Hotel
vanishes and becomes an Apartment.
Do you mean, you just want to take a Person, associated with some Hotel,
and move that Person to an Apartment? That would just be an UPDATE of
Person.accomodation_id. Just change the Person.accommodation attribute
to the parent record you want.
Not sure what you mean. You'd need to illustrate what rows you are
looking to modify for me to understand which one you are getting at.
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