--- /dev/null
+# TODO: make unit tests out of all this
+
+####### multiple table
+
+from sqlalchemy import *
+
+#db = create_engine('sqlite:///', echo=True)
+db = create_engine('postgres://scott:tiger@127.0.0.1/test', echo=True)
+metadata = BoundMetaData(db)
+
+session = create_session()
+
+class Employee(object):
+ def __init__(self, name):
+ self.name = name
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name
+
+class Manager(Employee):
+ def __init__(self, name, manager_data):
+ self.name = name
+ self.manager_data = manager_data
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.manager_data
+
+class Engineer(Employee):
+ def __init__(self, name, engineer_info):
+ self.name = name
+ self.engineer_info = engineer_info
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.engineer_info
+
+
+people = Table('people', metadata,
+ Column('person_id', Integer, primary_key=True),
+ Column('name', String(50)),
+ Column('type', String(30)))
+
+engineers = Table('engineers', metadata,
+ Column('person_id', Integer, ForeignKey('people.person_id'), primary_key=True),
+ Column('engineer_info', String(50)),
+ )
+
+managers = Table('managers', metadata,
+ Column('person_id', Integer, ForeignKey('people.person_id'), primary_key=True),
+ Column('manager_data', String(50)),
+ )
+
+people_managers = Table('people_managers', metadata,
+ Column('person_id', Integer, ForeignKey("people.person_id")),
+ Column('manager_id', Integer, ForeignKey("managers.person_id"))
+)
+
+person_join = polymorphic_union( {
+ 'engineer':people.join(engineers),
+ 'manager':people.join(managers),
+ 'person':people.select(people.c.type=='person'),
+ }, None, 'pjoin')
+
+
+
+
+person_mapper = mapper(Employee, people, select_table=person_join, polymorphic_on=person_join.c.type, polymorphic_identity='person',
+ properties = dict(managers = relation(Manager, secondary=people_managers, lazy=False))
+ )
+
+
+
+mapper(Engineer, engineers, inherits=person_mapper, polymorphic_identity='engineer')
+mapper(Manager, managers, inherits=person_mapper, polymorphic_identity='manager')
+
+
+
+def create_some_employees():
+ people.create()
+ engineers.create()
+ managers.create()
+ people_managers.create()
+ session.save(Manager('Tom', 'knows how to manage things'))
+ session.save(Engineer('Kurt', 'knows how to hack'))
+ session.flush()
+ session.query(Manager).select()
+try:
+ create_some_employees()
+finally:
+ metadata.drop_all()
+
+
+####### concrete table
+
+from sqlalchemy import *
+
+db = create_engine("sqlite:///:memory:")
+
+metadata = BoundMetaData(db)
+session = create_session()
+
+class Employee(object):
+ def __init__(self, name):
+ self.name = name
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name
+
+class Manager(Employee):
+ def __init__(self, name, manager_data):
+ self.name = name
+ self.manager_data = manager_data
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.manager_data
+
+class Engineer(Employee):
+ def __init__(self, name, engineer_info):
+ self.name = name
+ self.engineer_info = engineer_info
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.engineer_info
+
+
+managers_table = Table('managers', metadata,
+ Column('employee_id', Integer, primary_key=True),
+ Column('name', String(50)),
+ Column('manager_data', String(50)),
+).create()
+
+engineers_table = Table('engineers', metadata,
+ Column('employee_id', Integer, primary_key=True),
+ Column('name', String(50)),
+ Column('engineer_info', String(50)),
+).create()
+
+
+
+pjoin = polymorphic_union({
+ 'manager':managers_table,
+ 'engineer':engineers_table
+}, 'type', 'pjoin')
+
+employee_mapper = mapper(Employee, pjoin, polymorphic_on=pjoin.c.type)
+manager_mapper = mapper(Manager, managers_table, inherits=employee_mapper, concrete=True, polymorphic_identity='manager')
+engineer_mapper = mapper(Engineer, engineers_table, inherits=employee_mapper, concrete=True, polymorphic_identity='engineer')
+
+
+
+session.save(Manager('Tom', 'knows how to manage things'))
+session.save(Engineer('Kurt', 'knows how to hack'))
+session.flush()
+
+
+# this gives you [Engineer Kurt knows how to hack, Manager Tom knows how to manage things]
+# as it should be
+session.query(Employee).select()
+
+# this fails
+session.query(Engineer).select()
+
+# this fails
+session.query(Manager).select()
+
+
+############ single table
+from sqlalchemy import *
+
+db = create_engine("sqlite:///:memory:")
+
+metadata = BoundMetaData(db)
+session = create_session()
+
+class Employee(object):
+ def __init__(self, name):
+ self.name = name
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name
+
+class Manager(Employee):
+ def __init__(self, name, manager_data):
+ self.name = name
+ self.manager_data = manager_data
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.manager_data
+
+class Engineer(Employee):
+ def __init__(self, name, engineer_info):
+ self.name = name
+ self.engineer_info = engineer_info
+ def __repr__(self):
+ return self.__class__.__name__ + " " + self.name + " " + self.engineer_info
+
+
+employees_table = Table('employees', metadata,
+ Column('employee_id', Integer, primary_key=True),
+ Column('name', String(50)),
+ Column('manager_data', String(50)),
+ Column('engineer_info', String(50)),
+ Column('type', String(20))
+)
+
+employee_mapper = mapper(Employee, employees_table, polymorphic_on=employees_table.c.type)
+manager_mapper = mapper(Manager, inherits=employee_mapper, polymorphic_identity='manager')
+engineer_mapper = mapper(Engineer, inherits=employee_mapper, polymorphic_identity='engineer')
+
+
+employees_table.create()
+
+session.save(Manager('Tom', 'knows how to manage things'))
+session.save(Engineer('Kurt', 'knows how to hack'))
+session.flush()
+
+
+# this gives you [Engineer Kurt knows how to hack, Manager Tom knows how to manage things]
+# as it should be
+session.query(Employee).select()
+
+# this gives you [Engineer Kurt knows how to hack, Manager Tom knows how to manage things]
+# instead of [Engineer Kurt knows how to hack]
+session.query(Engineer).select()
+
+
+# this gives you [Engineer Kurt knows how to hack, Manager Tom knows how to manage things]
+# instead of [Manager Tom knows how to manage things]
+session.query(Manager).select()