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  • Committer: Package Import Robot
  • Author(s): Piotr Ożarowski, Jakub Wilk, Piotr Ożarowski
  • Date: 2013-07-06 20:53:52 UTC
  • mfrom: (1.4.23) (16.1.17 experimental)
  • Revision ID: package-import@ubuntu.com-20130706205352-ryppl1eto3illd79
Tags: 0.8.2-1
[ Jakub Wilk ]
* Use canonical URIs for Vcs-* fields.

[ Piotr Ożarowski ]
* New upstream release
* Upload to unstable
* Build depend on python3-all instead of -dev, extensions are not built for
  Python 3.X 

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examples/inheritance/polymorph.py
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from sqlalchemy import MetaData, Table, Column, Integer, String, \
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    ForeignKey, create_engine
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from sqlalchemy.orm import mapper, relationship, sessionmaker
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# this example illustrates a polymorphic load of two classes
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metadata = MetaData()
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# a table to store companies
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companies = Table('companies', metadata,
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   Column('company_id', Integer, primary_key=True),
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   Column('name', String(50)))
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# we will define an inheritance relationship between the table "people" and
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# "engineers", and a second inheritance relationship between the table
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# "people" and "managers"
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people = Table('people', metadata,
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   Column('person_id', Integer, primary_key=True),
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   Column('company_id', Integer, ForeignKey('companies.company_id')),
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   Column('name', String(50)),
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   Column('type', String(30)))
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engineers = Table('engineers', metadata,
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   Column('person_id', Integer, ForeignKey('people.person_id'),
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                                    primary_key=True),
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   Column('status', String(30)),
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   Column('engineer_name', String(50)),
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   Column('primary_language', String(50)),
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  )
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managers = Table('managers', metadata,
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   Column('person_id', Integer, ForeignKey('people.person_id'),
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                                    primary_key=True),
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   Column('status', String(30)),
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   Column('manager_name', String(50))
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   )
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# create our classes.  The Engineer and Manager classes extend from Person.
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class Person(object):
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    def __init__(self, **kwargs):
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        for key, value in kwargs.iteritems():
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            setattr(self, key, value)
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    def __repr__(self):
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        return "Ordinary person %s" % self.name
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class Engineer(Person):
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    def __repr__(self):
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        return "Engineer %s, status %s, engineer_name %s, "\
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                "primary_language %s" % \
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                    (self.name, self.status,
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                        self.engineer_name, self.primary_language)
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class Manager(Person):
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    def __repr__(self):
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        return "Manager %s, status %s, manager_name %s" % \
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                    (self.name, self.status, self.manager_name)
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class Company(object):
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    def __init__(self, **kwargs):
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        for key, value in kwargs.iteritems():
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            setattr(self, key, value)
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    def __repr__(self):
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        return "Company %s" % self.name
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person_mapper = mapper(Person, people, polymorphic_on=people.c.type,
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                       polymorphic_identity='person')
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mapper(Engineer, engineers, inherits=person_mapper,
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       polymorphic_identity='engineer')
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mapper(Manager, managers, inherits=person_mapper,
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       polymorphic_identity='manager')
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mapper(Company, companies, properties={'employees'
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       : relationship(Person, lazy='joined', backref='company',
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       cascade='all, delete-orphan')})
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engine = create_engine('sqlite://', echo=True)
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metadata.create_all(engine)
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session = sessionmaker(engine)()
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c = Company(name='company1')
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c.employees.append(Manager(name='pointy haired boss', status='AAB',
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                   manager_name='manager1'))
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c.employees.append(Engineer(name='dilbert', status='BBA',
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                   engineer_name='engineer1', primary_language='java'))
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c.employees.append(Person(name='joesmith', status='HHH'))
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c.employees.append(Engineer(name='wally', status='CGG',
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                   engineer_name='engineer2', primary_language='python'
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                   ))
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c.employees.append(Manager(name='jsmith', status='ABA',
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                   manager_name='manager2'))
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session.add(c)
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session.commit()
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c = session.query(Company).get(1)
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for e in c.employees:
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    print e, e._sa_instance_state.key, e.company
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assert set([e.name for e in c.employees]) == set(['pointy haired boss',
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        'dilbert', 'joesmith', 'wally', 'jsmith'])
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print "\n"
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dilbert = session.query(Person).filter_by(name='dilbert').one()
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dilbert2 = session.query(Engineer).filter_by(name='dilbert').one()
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assert dilbert is dilbert2
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dilbert.engineer_name = 'hes dibert!'
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session.commit()
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c = session.query(Company).get(1)
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for e in c.employees:
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    print e
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# illustrate querying using direct table access:
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print session.query(Engineer.engineer_name).\
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            select_from(engineers).\
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            filter(Engineer.primary_language=='python').\
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            all()
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session.delete(c)
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session.commit()
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