import sqlalchemy as sa
from sqlalchemy import orm

from pyalchemybiz.model import meta
from pyalchemybiz.model import customer

def init_model(engine):
    """Call me before using any of the tables or classes in the model."""
    
    sm = orm.sessionmaker(autoflush=True, transactional=True, bind=engine)

    meta.engine = engine
    meta.Session = orm.scoped_session(sm)

    customer.t_customer = sa.Table('customer', meta.metadata,
                                   autoload=True, autoload_with=engine)
    orm.mapper(customer.Customer, customer.t_customer)