orm.py 文件源码

def get_bind(obj):
    """
    Return the bind for given SQLAlchemy Engine / Connection / declarative
    model object.

    :param obj: SQLAlchemy Engine / Connection / declarative model object

    ::

        from sqlalchemy_utils import get_bind


        get_bind(session)  # Connection object

        get_bind(user)

    """
    if hasattr(obj, 'bind'):
        conn = obj.bind
    else:
        try:
            conn = object_session(obj).bind
        except UnmappedInstanceError:
            conn = obj

    if not hasattr(conn, 'execute'):
        raise TypeError(
            'This method accepts only Session, Engine, Connection and '
            'declarative model objects.'
        )
    return conn