CassandraByteStore

This will help you get started with Cassandra key-value stores. For detailed documentation of all CassandraByteStore features and configurations head to the API reference.

Overview

Cassandra is a NoSQL, row-oriented, highly scalable and highly available database.

Integration details

Class	Package	Local	JS support	Package downloads	Package latest
CassandraByteStore	langchain-community	✅	✅

Setup

The CassandraByteStore is an implementation of ByteStore that stores the data in your Cassandra instance. The store keys must be strings and will be mapped to the row_id column of the Cassandra table. The store bytes values are mapped to the body_blob column of the Cassandra table.

Installation

The LangChain CassandraByteStore integration lives in the langchain-community package. You'll also need to install the cassio package or the cassandra-driver package as a peer dependency depending on which initialization method you're using:

%pip install -qU langchain-community
%pip install -qU cassandra-driver
%pip install -qU cassio

You'll also need to create a cassandra.cluster.Session object, as described in the Cassandra driver documentation. The details vary (e.g. with network settings and authentication), but this might be something like:

Instantiation

You'll first need to create a cassandra.cluster.Session object, as described in the Cassandra driver documentation. The details vary (e.g. with network settings and authentication), but this might be something like:

from cassandra.cluster import Cluster

cluster = Cluster()
session = cluster.connect()

Then you can create your store! You'll also need to provide the name of an existing keyspace of the Cassandra instance:

from langchain_community.storage import CassandraByteStore

kv_store = CassandraByteStore(
    table="my_store",
    session=session,
    keyspace="<YOUR KEYSPACE>",
)

Usage

You can set data under keys like this using the mset method:

kv_store.mset(
    [
        ["key1", b"value1"],
        ["key2", b"value2"],
    ]
)

kv_store.mget(
    [
        "key1",
        "key2",
    ]
)

And you can delete data using the mdelete method:

kv_store.mdelete(
    [
        "key1",
        "key2",
    ]
)

kv_store.mget(
    [
        "key1",
        "key2",
    ]
)

Init using cassio

It's also possible to use cassio to configure the session and keyspace.

import cassio

cassio.init(contact_points="127.0.0.1", keyspace="<YOUR KEYSPACE>")

store = CassandraByteStore(
    table="my_store",
)

store.mset([("k1", b"v1"), ("k2", b"v2")])
print(store.mget(["k1", "k2"]))

API reference

For detailed documentation of all CassandraByteStore features and configurations, head to the API reference: https://python.langchain.com/api_reference/community/storage/langchain_community.storage.cassandra.CassandraByteStore.html

Related

• Key-value store conceptual guide