Astra DB

Compatibility

Only available on Node.js.

DataStax Astra DB is a serverless vector-capable database built on Apache Cassandra and made conveniently available through an easy-to-use JSON API.

Setup

1. Create an Astra DB account.
2. Create a vector enabled database.
3. Grab your API Endpoint and Token from the Database Details.
4. Set up the following env vars:

export ASTRA_DB_APPLICATION_TOKEN=YOUR_ASTRA_DB_APPLICATION_TOKEN_HERE
export ASTRA_DB_ENDPOINT=YOUR_ASTRA_DB_ENDPOINT_HERE
export ASTRA_DB_COLLECTION=YOUR_ASTRA_DB_COLLECTION_HERE
export OPENAI_API_KEY=YOUR_OPENAI_API_KEY_HERE

Where ASTRA_DB_COLLECTION is the desired name of your collection

1. Install the Astra TS Client & the LangChain community package

tip

See this section for general instructions on installing integration packages.

• npm
• Yarn
• pnpm

npm install @langchain/openai @datastax/astra-db-ts @langchain/community @langchain/core

Indexing docs

import { OpenAIEmbeddings } from "@langchain/openai";
import {
  AstraDBVectorStore,
  AstraLibArgs,
} from "@langchain/community/vectorstores/astradb";

const astraConfig: AstraLibArgs = {
  token: process.env.ASTRA_DB_APPLICATION_TOKEN as string,
  endpoint: process.env.ASTRA_DB_ENDPOINT as string,
  collection: process.env.ASTRA_DB_COLLECTION ?? "langchain_test",
  collectionOptions: {
    vector: {
      dimension: 1536,
      metric: "cosine",
    },
  },
};

const vectorStore = await AstraDBVectorStore.fromTexts(
  [
    "AstraDB is built on Apache Cassandra",
    "AstraDB is a NoSQL DB",
    "AstraDB supports vector search",
  ],
  [{ foo: "foo" }, { foo: "bar" }, { foo: "baz" }],
  new OpenAIEmbeddings(),
  astraConfig
);

// Querying docs:
const results = await vectorStore.similaritySearch("Cassandra", 1);

// or filtered query:
const filteredQueryResults = await vectorStore.similaritySearch("A", 1, {
  foo: "bar",
});

API Reference:

• OpenAIEmbeddings from @langchain/openai
• AstraDBVectorStore from @langchain/community/vectorstores/astradb
• AstraLibArgs from @langchain/community/vectorstores/astradb

Vector Types

Astra DB supports cosine (the default), dot_product, and euclidean similarity search; this is defined when the vector store is first created as part of the CreateCollectionOptions:

  vector: {
      dimension: number;
      metric?: "cosine" | "euclidean" | "dot_product";
  };

Related

• Vector store conceptual guide
• Vector store how-to guides