Adding data to a inherited class in SQLAlchemy

Question

I'm trying to create a database to store people and addresses: home and work. I've used inherited classes to create both addresses.

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import ForeignKey, Column, Integer, String, Float
from sqlalchemy.orm import relationship

Base = declarative_base()

class Colleague(Base):
""" Generic Colleague """
    __tablename__ = 'colleagues'
    id = Column(Integer, primary_key=True)
    first_name = Column(String(50))
    last_name = Column(String(50))
    home_address = relationship('Home_Address', back_populates='colleague')
    work_address = relationship('Work_Address', back_populates='colleague')

class Address(Base):
    """ Generic Address """
    __tablename__ = 'addresses'
    id = Column(Integer, primary_key=True)
    adr_type = Column('type', String(50))
    country = Column(String(50))
    state = Column(String(50))
    county = Column(String(50))
    city = Column(String(50))
    district = Column(String(50))
    street = Column(String(50))
    house_number = Column(Integer)
    postal_code = Column(String(50))

    __mapper_args__ = {
        'polymorphic_on' : adr_type
    }

    class Home_Address(Address):
    __tablename__ = 'home_addresses'
    id = Column(Integer, ForeignKey('addresses.id'), primary_key=True)
    colleague_id = Column(Integer, ForeignKey('colleagues.id'))
    colleague = relationship('Colleague', back_populates='home_address')
    __mapper_args__ = {
        'polymorphic_identity' : 'home_addresses'
    }

class Work_Address(Address):
    __tablename__ = 'work_addresses'
    id = Column(Integer, ForeignKey('addresses.id'), primary_key=True)
    colleague_id = Column(Integer, ForeignKey('colleagues.id'))
    colleague = relationship('Colleague', back_populates='work_address')
    __mapper_args__ = {
        'polymorphic_identity' : 'work_addresses'
    }

I've then tried to add an address to a colleague,

adr1 = Home_Address(country='France', city='Paris')
adr2 = Work_Address(country='France', city='Lyon')
col = Colleague(first_name='Joe', last_name='Dalton')
col.home_address = adr1
col.work_address = adr2

but this happens:

TypeError: Incompatible collection type: Home_Address is not list-like

col.home_address gives an empty list, instead of giving me the object Home_Address, how can I set it up to work? Or maybe there is a simpler way of doing it ?

dizzyf · Accepted Answer · 2017-03-24 17:28:42Z

1

Colleague -> Address(es) is a one-to-many relationship, right? That would expect a list, so maybe try something like this:

adr1 = Home_Address(country='France', city='Paris')
adr2 = Work_Address(country='France', city='Lyon')
col = Colleague(first_name='Joe', last_name='Dalton')
col.home_address = [adr1]
col.work_address = [adr2]

answered Mar 24, 2017 at 17:28

dizzyf

3,7233 gold badges22 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Charleess Over a year ago

That's it, I thought it would need the object, but making it a list works. Thanks !!

TheArchitect Over a year ago

You can also add the kwarg uselist=False to the relationship to have SQLA map it to an object instead of a collection.

Collectives™ on Stack Overflow

Adding data to a inherited class in SQLAlchemy

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related