- removed the ancient "polymorphic association"

examples and replaced with an updated set of
examples that use declarative mixins,
"generic_associations".   Each presents an alternative
table layout.

1 files changed, 0 insertions, 156 deletions

diff --git a/examples/poly_assoc/poly_assoc.py b/examples/poly_assoc/poly_assoc.py
deleted file mode 100644
index 1854bfa3d..000000000
--- a/examples/poly_assoc/poly_assoc.py
+++ /dev/null
@@ -1,156 +0,0 @@
-"""
-"polymorphic" associations, ala ActiveRecord.
-
-In this example, we are specifically targeting this ActiveRecord
-functionality:
-
-http://wiki.rubyonrails.org/rails/pages/UnderstandingPolymorphicAssociations
-
-The term "polymorphic" here means "object X can be referenced by objects A, B,
-and C, along a common line of association".
-
-In this example we illustrate the relationship in both directions. A little
-bit of property magic is used to smooth the edges.
-
-AR creates this relationship in such a way that disallows any foreign key
-constraint from existing on the association. For a different way of doing
-this, see poly_assoc_fks.py. The interface is the same, the efficiency is more
-or less the same, but foreign key constraints may be used. That example also
-better separates the associated target object from those which associate with
-it.
-
-"""
-
-from sqlalchemy import MetaData, Table, Column, Integer, String, and_
-from sqlalchemy.orm import mapper, relationship, sessionmaker, \
-    class_mapper, backref
-
-metadata = MetaData('sqlite://')
-
-#######
-# addresses table, class, 'addressable interface'.
-
-addresses = Table("addresses", metadata,
-    Column('id', Integer, primary_key=True),
-    Column('addressable_id', Integer),
-    Column('addressable_type', String(50)),
-    Column('street', String(100)),
-    Column('city', String(50)),
-    Column('country', String(50))
-    )
-
-class Address(object):
-    def __init__(self, type):
-        self.addressable_type = type
-    @property
-    def member(self):
-        return getattr(self, '_backref_%s' % self.addressable_type)
-
-def addressable(cls, name, uselist=True):
-    """addressable 'interface'.
-
-    if you really wanted to make a "generic" version of this function, it's
-    straightforward.
-    """
-
-    # create_address function, imitaes the rails example.
-    # we could probably use property tricks as well to set
-    # the Address object's "addressabletype" attribute.
-    def create_address(self):
-        a = Address(table.name)
-        if uselist:
-            getattr(self, name).append(a)
-        else:
-            setattr(self, name, a)
-        return a
-
-    mapper = class_mapper(cls)
-    table = mapper.local_table
-    cls.create_address = create_address
-    # no constraints.  therefore define constraints in an ad-hoc fashion.
-    primaryjoin = and_(
-            list(table.primary_key)[0] == addresses.c.addressable_id,
-            addresses.c.addressable_type == table.name
-     )
-    foreign_keys = [addresses.c.addressable_id]
-    mapper.add_property(name, relationship(
-            Address,
-            primaryjoin=primaryjoin, 
-            uselist=uselist, 
-            foreign_keys=foreign_keys,
-            backref=backref('_backref_%s' % table.name, 
-                            primaryjoin=list(table.primary_key)[0] ==\
-                                        addresses.c.addressable_id, 
-                            foreign_keys=foreign_keys)
-        )
-    )
-
-mapper(Address, addresses)
-
-######
-# sample # 1, users
-
-users = Table("users", metadata,
-    Column('id', Integer, primary_key=True),
-    Column('name', String(50), nullable=False)
-    )
-
-class User(object):
-    pass
-
-mapper(User, users)
-addressable(User, 'addresses', uselist=True)
-
-######
-# sample # 2, orders
-
-orders = Table("orders", metadata,
-    Column('id', Integer, primary_key=True),
-    Column('description', String(50), nullable=False))
-
-class Order(object):
-    pass
-
-mapper(Order, orders)
-addressable(Order, 'address', uselist=False)
-
-
-######
-# use it !
-metadata.create_all()
-
-u1 = User()
-u1.name = 'bob'
-
-o1 = Order()
-o1.description = 'order 1'
-
-a1 = u1.create_address()
-a1.street = '123 anywhere street'
-a2 = u1.create_address()
-a2.street = '345 orchard ave'
-
-a3 = o1.create_address()
-a3.street = '444 park ave.'
-
-sess = sessionmaker()()
-sess.add(u1)
-sess.add(o1)
-
-sess.commit()
-
-# query objects, get their addresses
-
-bob = sess.query(User).filter_by(name='bob').one()
-assert [s.street for s in bob.addresses] == ['123 anywhere street', '345 orchard ave']
-
-order = sess.query(Order).filter_by(description='order 1').one()
-assert order.address.street == '444 park ave.'
-
-# query from Address to members
-
-for address in sess.query(Address).all():
-    print "Street", address.street, "Member", address.member
-
-
-