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.

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Overview

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

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Integration details

ClassPackageLocalJS supportPackage downloadsPackage latest
CassandraByteStorelangchain-community✅✅PyPI - DownloadsPyPI - Version

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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.

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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:

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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>",
)

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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",
    ]
)

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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"]))

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API reference

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