database.py

database.py

# -*- coding:utf-8 -*-

class LoupQuery(Query):
    pass
        
        
db_session = scoped_session(
    sessionmaker(
        autocommit=False,
        autoflush=False,
        expire_on_commit=False,
        bind=db_engine,
        query_cls=LoupQuery
    )
)

class LoupBase(object):
    @declared_attr
    def query(cls):
        query_cls = getattr(cls, 'query_cls', LoupQuery)
        return db_session.query_property(query_cls=query_cls)


Base = declarative_base(cls=LoupBase)


class Item(Base):
    name = Column(Unicode(30), nullable=False)
    price = Column(Float, nullable=False)
    
    class ItemQuery(LoupQuery):
        def filter_by_name(self, name):
            return self.filter(Item.name == name)
        
        def filter_by_price(self, price):
            return self.filter(Item.price == price)
        
    query_cls = ItemQuery


>>> Item.query.filter_by_name(u'test').filter_by_price(100)