Method prepare

cassandra/cluster.py:3141–3205

Prepares a query string, returning a :class:`~cassandra.query.PreparedStatement` instance which can be used as follows:: >>> session = cluster.connect("mykeyspace") >>> query = "INSERT INTO users (id, name, age) VALUES (?, ?, ?)" >>> prepared = s

(self, query, custom_payload=None, keyspace=None)

            fn(response_future, *args, **kwargs)

    def prepare(self, query, custom_payload=None, keyspace=None):
        """
        Prepares a query string, returning a :class:`~cassandra.query.PreparedStatement`
        instance which can be used as follows::

            >>> session = cluster.connect("mykeyspace")
            >>> query = "INSERT INTO users (id, name, age) VALUES (?, ?, ?)"
            >>> prepared = session.prepare(query)
            >>> session.execute(prepared, (user.id, user.name, user.age))

        Or you may bind values to the prepared statement ahead of time::

            >>> prepared = session.prepare(query)
            >>> bound_stmt = prepared.bind((user.id, user.name, user.age))
            >>> session.execute(bound_stmt)

        Of course, prepared statements may (and should) be reused::

            >>> prepared = session.prepare(query)
            >>> for user in users:
            ...     bound = prepared.bind((user.id, user.name, user.age))
            ...     session.execute(bound)

        Alternatively, if :attr:`~.Cluster.protocol_version` is 5 or higher
        (requires Cassandra 4.0+), the keyspace can be specified as a
        parameter. This will allow you to avoid specifying the keyspace in the
        query without specifying a keyspace in :meth:`~.Cluster.connect`. It
        even will let you prepare and use statements against a keyspace other
        than the one originally specified on connection:

            >>> analyticskeyspace_prepared = session.prepare(
            ...     "INSERT INTO user_activity id, last_activity VALUES (?, ?)",
            ...     keyspace="analyticskeyspace")  # note the different keyspace

        **Important**: PreparedStatements should be prepared only once.
        Preparing the same query more than once will likely affect performance.

        `custom_payload` is a key value map to be passed along with the prepare
        message. See :ref:`custom_payload`.
        """
        message = PrepareMessage(query=query, keyspace=keyspace)
        future = ResponseFuture(self, message, query=None, timeout=self.default_timeout)
        try:
            future.send_request()
            response = future.result().one()
        except Exception:
            log.exception("Error preparing query:")
            raise

        prepared_keyspace = keyspace if keyspace else None
        prepared_statement = PreparedStatement.from_message(
            response.query_id, response.bind_metadata, response.pk_indexes, self.cluster.metadata, query, prepared_keyspace,
            self._protocol_version, response.column_metadata, response.result_metadata_id, self.cluster.column_encryption_policy)
        prepared_statement.custom_payload = future.custom_payload

        self.cluster.add_prepared(response.query_id, prepared_statement)

        if self.cluster.prepare_on_all_hosts: