gistfile1.py

    ###########
    # ACCOUNT #
    ###########

    orm.mapper(Account, table['account'])

    ########
    # POOL #
    ########

    orm.mapper(Pool, table['pool'], properties = {
        'owner' : orm.relationship(
            Account,
            innerjoin = True,
            backref = 'pools'
         ),

         'facilitators' : orm.relationship(
            Account,
            secondary = table['account_role'],
            secondaryjoin = lambda : sql.and_(
                Account.id == AccountRole.account_id,
                AccountRole.role_id == Role.id,
                Role.name == 'facilitator'
            ),
            backref = 'facilitated_pools'
        )
    })

    ########
    # ROLE #
    ########

    orm.mapper(Role, table['role'])

    ################
    # ACCOUNT ROLE #
    ################

    orm.mapper(AccountRole, table['account_role'], properties = {
        'human' : orm.relationship(
            Account,
            lazy = 'joined',
            innerjoin = True,
            backref = 'assigned'
        ),

        'role' : orm.relationship(
            Role,
            lazy = 'joined',
            innerjoin = True,
            backref = 'assigned'
        ),

        'pool' : orm.relationship(
            Pool,
            backref = 'assigned'
        )
    })