Weaviate

Weaviate vector database integration

Overview

Weaviate is an open-source vector database with built-in vectorization, hybrid search, and GraphQL API support.

Installation

npm install @llamaindex/weaviate weaviate-ts-client

Basic Usage

import { WeaviateVectorStore } from "@llamaindex/weaviate";
import { VectorStoreIndex, Document } from "llamaindex";

const vectorStore = new WeaviateVectorStore({
  url: "http://localhost:8080",
  className: "MyDocuments"
});

const documents = [
  new Document({ text: "LlamaIndex is a data framework." }),
  new Document({ text: "Weaviate is a vector database." })
];

const index = await VectorStoreIndex.fromDocuments(documents, {
  storageContext: { vectorStore }
});

const queryEngine = index.asQueryEngine();
const response = await queryEngine.query({
  query: "What is Weaviate?"
});

Constructor Options

url · string · default: "http://localhost:8080"

Weaviate server URL

className · string · required

Name of the Weaviate class (collection)

apiKey · string

API key for Weaviate Cloud

Running Weaviate

Docker

docker run -p 8080:8080 \
  -e AUTHENTICATION_ANONYMOUS_ACCESS_ENABLED=true \
  -e PERSISTENCE_DATA_PATH=/var/lib/weaviate \
  semitechnologies/weaviate:latest

Weaviate Cloud

Sign up at Weaviate Cloud and use the provided URL:

const vectorStore = new WeaviateVectorStore({
  url: "https://my-cluster.weaviate.network",
  apiKey: process.env.WEAVIATE_API_KEY,
  className: "MyDocuments"
});

Schema Configuration

import weaviate from "weaviate-ts-client";

const client = weaviate.client({
  scheme: "http",
  host: "localhost:8080"
});

await client.schema
  .classCreator()
  .withClass({
    class: "MyDocuments",
    vectorizer: "none",  // Use external embeddings
    properties: [
      {
        name: "text",
        dataType: ["text"]
      },
      {
        name: "metadata",
        dataType: ["object"]
      }
    ]
  })
  .do();

Querying

Basic Query

const index = await VectorStoreIndex.fromVectorStore(vectorStore);

const retriever = index.asRetriever({
  similarityTopK: 5
});

const nodes = await retriever.retrieve("query text");

Metadata Filtering

const documents = [
  new Document({
    text: "Doc 1",
    metadata: { category: "tech", year: 2023 }
  })
];

const retriever = index.asRetriever({
  filters: {
    where: {
      path: ["category"],
      operator: "Equal",
      valueString: "tech"
    }
  }
});

Hybrid Search

Combine vector and keyword search:

const results = await client.graphql
  .get()
  .withClassName("MyDocuments")
  .withHybrid({
    query: "search query",
    alpha: 0.7  // 0 = keyword, 1 = vector
  })
  .withFields("text")
  .withLimit(5)
  .do();

Complete Example

import { WeaviateVectorStore } from "@llamaindex/weaviate";
import { VectorStoreIndex, Document, Settings } from "llamaindex";
import { OpenAI, OpenAIEmbedding } from "@llamaindex/openai";
import weaviate from "weaviate-ts-client";

// Configure settings
Settings.llm = new OpenAI({ model: "gpt-4" });
Settings.embedModel = new OpenAIEmbedding();

// Create schema
const client = weaviate.client({
  scheme: "http",
  host: "localhost:8080"
});

await client.schema
  .classCreator()
  .withClass({
    class: "Documents",
    vectorizer: "none"
  })
  .do();

// Create vector store
const vectorStore = new WeaviateVectorStore({
  url: "http://localhost:8080",
  className: "Documents"
});

// Build index
const documents = [
  new Document({ text: "LlamaIndex documentation..." })
];

const index = await VectorStoreIndex.fromDocuments(documents, {
  storageContext: { vectorStore }
});

// Query
const queryEngine = index.asQueryEngine();
const response = await queryEngine.query({
  query: "What is LlamaIndex?"
});

Best Practices

1. Use Weaviate Cloud for production: Managed solution
2. Enable persistence: Configure data persistence in Docker
3. Leverage hybrid search: Combine vector and keyword search
4. Define proper schema: Plan properties and data types
5. Use GraphQL for complex queries: Direct access to Weaviate’s API

See Also

• Weaviate Documentation
• Weaviate Cloud
• Vector Store Index