Ticket #78: test_polymorphic_rel.py

from elixir import *

# TODO: this usecase (explicit "inverse" on child entity) is buggy: it adds a
# backref on some_a, which means, the relation appears on A and C objects in
# addition to B !!!
# solution: 1) do not allow such inverse to be specified (and change exception
#              message)
#       and 2) allow the OneToMany relationship to exist anyway, if the user
#              passes manual primary_join (involving the col created by the
#              M2O) OR backref=False
class A(Entity):
    pass

class B(A):
    many_other = OneToMany('Other', inverse='some_a')

class C(A):
    pass
    #many_other = OneToMany('Other')

class Other(Entity):
    some_a = ManyToOne('A')


metadata.bind = 'sqlite:///'
setup_all(True)

a1 = A()
b1 = B()
c1 = C()
o1 = Other(some_a=a1)
o2 = Other(some_a=b1)
o3 = Other(some_a=c1)

print "b1", b1.many_other
print "c1", c1.many_other

session.commit()

print "*" * 20, "A", "*" * 20
for a in session.query(A).all():
    print "a", a,
    if hasattr(a, 'many_other'):
        print "->", a.many_other
    else:
        print
print "*" * 20, "Other", "*" * 20
for o in session.query(Other).all():
    print o, "->", o.some_a