def __init__(self, host_, port_, db_name_):
        database.__init__(self, host_, port_, db_name_)
        self.users = self.db['mir_users']
        if not self._is_index_presented(self.users):
            log.info("creating index for users")
            self.users.create_index('name', ASCENDING, unique=True)

        self.clust = self.db['clust']
    def __init__(self, truncate=False):
        database.__init__(self, host_=local_host, port_=local_port, db_name_=local_db_name)
        self._schema_init()

        if truncate:
            self.db.drop_collection(self.nodes)
            self.db.drop_collection(self.relations)
            self.db.drop_collection(self.model_parameters)
            self._schema_init()