colanderalchemy_question_inheritance_backref

colander_experiment.py

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

import colander

from sqlalchemy import event
from sqlalchemy.orm import mapper
from colanderalchemy import setup_schema

import pprint

event.listen(mapper, 'mapper_configured', setup_schema)

Base = declarative_base()

class Person(Base):
    __tablename__ = 'person'

    satype = Column(String(50))
    __mapper_args__ = {
        'polymorphic_identity': 'person',
        'polymorphic_on': satype
    }

    __colanderalchemy_config__ = {
        'excludes': ['surname']
    }

    id = Column(Integer, primary_key=True)
    name = Column(String(128))
    surname = Column(String(128))
    a_number = Column(Integer(), info={
            'colanderalchemy': {
                'typ': colander.Float()
            }
        }
    )


class Gamer(Person):
    __tablename__ = 'gamer'

    __mapper_args__ = {
        'polymorphic_identity': 'gamer',
    }

    __colanderalchemy_config__ = {
        'excludes': ['satype']
    }

    id = Column(Integer, ForeignKey('person.id'), primary_key=True)
    high_score = Column(Integer)


# class Gamer(Base):
#     __tablename__ = 'gamer'

#     id = Column(Integer, primary_key=True)
#     name = Column(String(128))
#     surname = Column(String(128))
#     high_score = Column(Integer)


class Score(Base):
    __tablename__ = 'score'

    id = Column(Integer, primary_key=True)
    gamer_id = Column(Integer, ForeignKey('gamer.id'))
    gamer = relationship('Gamer', backref='scores')
    value = Column(Integer)


# class Score(Base):
#     __tablename__ = 'score'

#     id = Column(Integer, primary_key=True)
#     gamer_id = Column(Integer, ForeignKey('person.id'))
#     gamer = relationship('Person', backref='scores')
#     value = Column(Integer)


engine = create_engine('sqlite:///:memory:', echo=False)
Base.metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()

gamer = Gamer(name='Jayne', surname='Cobb', a_number=123)
session.add(gamer)

score1 = Score(value=1000, gamer=gamer)
score2 = Score(value=2000, gamer=gamer)
session.add(score1)
session.add(score2)

session.commit()

# Check that the backref is functioning (it is):
print 'Scores', [score.value for score in gamer.scores]
print

# Print a score, the relationship mapping is used to display the gamer
# serialization inline
schema = Score.__colanderalchemy__
print 'Score 1'
pprint.pprint(schema.serialize(schema.dictify(score1)))
print

# Print the gamer. The relationship backref is not used to display the
# serializations of the scores inline
schema = Gamer.__colanderalchemy__
print 'Gamer'
pprint.pprint(schema.serialize(schema.dictify(gamer)))