以编程方式使用文档

> Azure DocumentDB 它让您可以轻松创建具有完整原生 MongoDB 支持的数据库。您可以运用您的 MongoDB 经验，继续使用您喜爱的 MongoDB 驱动程序、SDK 和工具，只需将应用程序指向连接字符串即可。使用 Azure DocumentDB 中的向量搜索，可以将基于 AI 的应用程序与存储在 Azure DocumentDB 中的数据无缝集成。

Azure DocumentDB 为开发人员提供完全托管的 MongoDB 兼容数据库服务，用于使用熟悉的架构构建现代化应用程序。

了解如何利用 Azure DocumentDB 的向量搜索功能，请参阅 本页面。如果您没有 Azure 账户，可以 创建免费账户 开始使用。

设置

首先需要安装 @langchain/azure-cosmosdb package:

npm install @langchain/azure-cosmosdb @langchain/core

还需要运行一个 Azure DocumentDB 实例。您可以按照 本指南.

在 Azure Portal 上免费部署一个免费版本。实例运行后，确保您拥有连接字符串和管理密钥。您可以在 Azure Portal 上实例的“连接字符串”部分找到它们。然后需要设置以下环境变量：

AZURE_DOCUMENTDB_CONNECTION_STRING=

示例

以下示例从 Azure DocumentDB 中的文件索引文档，运行向量搜索查询，最后使用链根据检索到的文档用自然语言回答问题 。

  AzureDocumentDBVectorStore,
  AzureDocumentDBSimilarityType,
} from "@langchain/azure-cosmosdb";







// Load documents from file
const loader = new TextLoader("./state_of_the_union.txt");
const rawDocuments = await loader.load();
const splitter = new RecursiveCharacterTextSplitter({
  chunkSize: 1000,
  chunkOverlap: 0,
});
const documents = await splitter.splitDocuments(rawDocuments);

// Create Azure DocumentDB vector store
const store = await AzureDocumentDBVectorStore.fromDocuments(
  documents,
  new OpenAIEmbeddings(),
  {
    databaseName: "langchain",
    collectionName: "documents",
    indexOptions: {
      numLists: 100,
      dimensions: 1536,
      similarity: AzureDocumentDBSimilarityType.COS,
    },
  }
);

// Performs a similarity search
const resultDocuments = await store.similaritySearch(
  "What did the president say about Ketanji Brown Jackson?"
);

console.log("Similarity search results:");
console.log(resultDocuments[0].pageContent);
/*
  Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you're at it, pass the Disclose Act so Americans can know who is funding our elections.

  Tonight, I'd like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service.

  One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court.

  And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation's top legal minds, who will continue Justice Breyer's legacy of excellence.
*/

// Use the store as part of a chain
const model = new ChatOpenAI({ model: "gpt-3.5-turbo-1106" });
const questionAnsweringPrompt = ChatPromptTemplate.fromMessages([
  [
    "system",
    "Answer the user's questions based on the below context:\n\n{context}",
  ],
  ["human", "{input}"],
]);

const combineDocsChain = await createStuffDocumentsChain({
  llm: model,
  prompt: questionAnsweringPrompt,
});

const chain = await createRetrievalChain({
  retriever: store.asRetriever(),
  combineDocsChain,
});

const res = await chain.invoke({
  input: "What is the president's top priority regarding prices?",
});

console.log("Chain response:");
console.log(res.answer);
/*
  The president's top priority is getting prices under control.
*/

// Clean up
await store.delete();

await store.close();

相关