[Sqlalchemy-tickets] [sqlalchemy] #2751: assocaition proxy support for scalar-targeted attributes

[sqlalchemy <mi...@zz...>]

#2751: assocaition proxy support for scalar-targeted attributes
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 Reporter:  zzzeek  |           Owner:  zzzeek
     Type:  defect  |          Status:  new
 Priority:  medium  |       Milestone:  0.8.xx
Component:  ext     |        Severity:  minor - half an hour
 Keywords:          |  Progress State:  in progress
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 {{{
 #!python
 from sqlalchemy.engine import create_engine
 from sqlalchemy.ext.associationproxy import association_proxy
 from sqlalchemy.ext.declarative.api import declarative_base
 from sqlalchemy.orm import relationship
 from sqlalchemy.orm.session import sessionmaker
 from sqlalchemy.schema import Column, ForeignKey
 from sqlalchemy.types import Integer, String

 Base = declarative_base()

 class A(Base):
     __tablename__ = 'table_a'
     id = Column(Integer, primary_key=True)
     color = Column(String)
     def __init__(self, color):
         self.color = color

 class B(Base):
     __tablename__ = 'table_b'
     id = Column(Integer, primary_key=True)
     a_id = Column(Integer, ForeignKey('table_a.id'))
     a_re = relationship('A', backref='b_re')
     a_color = association_proxy('a_re', 'color')


 if __name__ == '__main__':
     engine = create_engine('sqlite:///:memory:', echo=True)
     Session = sessionmaker(engine)
     session = Session()
     Base.metadata.create_all(engine)

     b1 = B()
     b2 = B()
     b3 = B()
     b4 = B()

     b1.a_color = 'blue'
     b2.a_re = A(color=None)

     session.add_all([b1, b2, b3, b4])

     q = session.query(B).filter(B.a_color == None).all()
     p = session.query(B).filter(B.a_color != None).all()

     # will also add a special feature for this
     r = session.query(B).filter(B.a_color.has()).all()

     assert q == [b2, b3, b4]
     assert p == [b1]
     assert r == [b1, b2]
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2751>
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