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                *   [Chroma Self Query Retriever](/v0.1/docs/modules/data_connection/retrievers/self_query/chroma-self-query/)
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*   [](/v0.1/)
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*   [Self-querying](/v0.1/docs/modules/data_connection/retrievers/self_query/)
*   Memory Vector Store Self Query Retriever

On this page

Memory Vector Store Self Query Retriever
========================================

This example shows how to use a self query retriever with a basic, in-memory vector store.

Usage[​](#usage "Direct link to Usage")
---------------------------------------

tip

See [this section for general instructions on installing integration packages](/v0.1/docs/get_started/installation/#installing-integration-packages).

*   npm
*   Yarn
*   pnpm

    npm install @langchain/openai

    yarn add @langchain/openai

    pnpm add @langchain/openai

    import { MemoryVectorStore } from "langchain/vectorstores/memory";import { AttributeInfo } from "langchain/schema/query_constructor";import { OpenAIEmbeddings, OpenAI } from "@langchain/openai";import { SelfQueryRetriever } from "langchain/retrievers/self_query";import { FunctionalTranslator } from "langchain/retrievers/self_query/functional";import { Document } from "@langchain/core/documents";/** * First, we create a bunch of documents. You can load your own documents here instead. * Each document has a pageContent and a metadata field. Make sure your metadata matches the AttributeInfo below. */const docs = [  new Document({    pageContent:      "A bunch of scientists bring back dinosaurs and mayhem breaks loose",    metadata: { year: 1993, rating: 7.7, genre: "science fiction" },  }),  new Document({    pageContent:      "Leo DiCaprio gets lost in a dream within a dream within a dream within a ...",    metadata: { year: 2010, director: "Christopher Nolan", rating: 8.2 },  }),  new Document({    pageContent:      "A psychologist / detective gets lost in a series of dreams within dreams within dreams and Inception reused the idea",    metadata: { year: 2006, director: "Satoshi Kon", rating: 8.6 },  }),  new Document({    pageContent:      "A bunch of normal-sized women are supremely wholesome and some men pine after them",    metadata: { year: 2019, director: "Greta Gerwig", rating: 8.3 },  }),  new Document({    pageContent: "Toys come alive and have a blast doing so",    metadata: { year: 1995, genre: "animated" },  }),  new Document({    pageContent: "Three men walk into the Zone, three men walk out of the Zone",    metadata: {      year: 1979,      director: "Andrei Tarkovsky",      genre: "science fiction",      rating: 9.9,    },  }),];/** * Next, we define the attributes we want to be able to query on. * in this case, we want to be able to query on the genre, year, director, rating, and length of the movie. * We also provide a description of each attribute and the type of the attribute. * This is used to generate the query prompts. */const attributeInfo: AttributeInfo[] = [  {    name: "genre",    description: "The genre of the movie",    type: "string or array of strings",  },  {    name: "year",    description: "The year the movie was released",    type: "number",  },  {    name: "director",    description: "The director of the movie",    type: "string",  },  {    name: "rating",    description: "The rating of the movie (1-10)",    type: "number",  },  {    name: "length",    description: "The length of the movie in minutes",    type: "number",  },];/** * Next, we instantiate a vector store. This is where we store the embeddings of the documents. * We also need to provide an embeddings object. This is used to embed the documents. */const embeddings = new OpenAIEmbeddings();const llm = new OpenAI();const documentContents = "Brief summary of a movie";const vectorStore = await MemoryVectorStore.fromDocuments(docs, embeddings);const selfQueryRetriever = SelfQueryRetriever.fromLLM({  llm,  vectorStore,  documentContents,  attributeInfo,  /**   * We need to use a translator that translates the queries into a   * filter format that the vector store can understand. We provide a basic translator   * translator here, but you can create your own translator by extending BaseTranslator   * abstract class. Note that the vector store needs to support filtering on the metadata   * attributes you want to query on.   */  structuredQueryTranslator: new FunctionalTranslator(),});/** * Now we can query the vector store. * We can ask questions like "Which movies are less than 90 minutes?" or "Which movies are rated higher than 8.5?". * We can also ask questions like "Which movies are either comedy or drama and are less than 90 minutes?". * The retriever will automatically convert these questions into queries that can be used to retrieve documents. */const query1 = await selfQueryRetriever.invoke(  "Which movies are less than 90 minutes?");const query2 = await selfQueryRetriever.invoke(  "Which movies are rated higher than 8.5?");const query3 = await selfQueryRetriever.invoke(  "Which movies are directed by Greta Gerwig?");const query4 = await selfQueryRetriever.invoke(  "Which movies are either comedy or drama and are less than 90 minutes?");console.log(query1, query2, query3, query4);

#### API Reference:

*   [MemoryVectorStore](https://api.js.langchain.com/classes/langchain_vectorstores_memory.MemoryVectorStore.html) from `langchain/vectorstores/memory`
*   [AttributeInfo](https://api.js.langchain.com/classes/langchain_schema_query_constructor.AttributeInfo.html) from `langchain/schema/query_constructor`
*   [OpenAIEmbeddings](https://api.js.langchain.com/classes/langchain_openai.OpenAIEmbeddings.html) from `@langchain/openai`
*   [OpenAI](https://api.js.langchain.com/classes/langchain_openai.OpenAI.html) from `@langchain/openai`
*   [SelfQueryRetriever](https://api.js.langchain.com/classes/langchain_retrievers_self_query.SelfQueryRetriever.html) from `langchain/retrievers/self_query`
*   [FunctionalTranslator](https://api.js.langchain.com/classes/langchain_core_structured_query.FunctionalTranslator.html) from `langchain/retrievers/self_query/functional`
*   [Document](https://api.js.langchain.com/classes/langchain_core_documents.Document.html) from `@langchain/core/documents`

You can also initialize the retriever with default search parameters that apply in addition to the generated query:

    const selfQueryRetriever = SelfQueryRetriever.fromLLM({  llm,  vectorStore,  documentContents,  attributeInfo,  /**   * We need to use a translator that translates the queries into a   * filter format that the vector store can understand. We provide a basic translator   * translator here, but you can create your own translator by extending BaseTranslator   * abstract class. Note that the vector store needs to support filtering on the metadata   * attributes you want to query on.   */  structuredQueryTranslator: new FunctionalTranslator(),  searchParams: {    filter: (doc: Document) => doc.metadata && doc.metadata.rating > 8.5,    mergeFiltersOperator: "and",  },});

* * *

#### Help us out by providing feedback on this documentation page:

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