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Chroma Self Query Retriever

This example shows how to use a self query retriever with a Chroma vector store.

Usage

npm install @langchain/openai @langchain/community
import { OpenAIEmbeddings, OpenAI } from "@langchain/openai";
import { SelfQueryRetriever } from "langchain/retrievers/self_query";
import { ChromaTranslator } from "@langchain/community/structured_query/chroma";
import { Chroma } from "@langchain/community/vectorstores/chroma";
import { Document } from "@langchain/core/documents";
import type { AttributeInfo } from "langchain/chains/query_constructor";

/**
* 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 Chroma.fromDocuments(docs, embeddings, {
collectionName: "a-movie-collection",
});
const selfQueryRetriever = SelfQueryRetriever.fromLLM({
llm,
vectorStore,
documentContents,
attributeInfo,
/**
* We need to create a basic 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 ChromaTranslator(),
});

/**
* 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:

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 create a basic 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 ChromaTranslator(),
searchParams: {
filter: {
rating: {
$gt: 8.5,
},
},
mergeFiltersOperator: "and",
},
});

See the official docs for a full list of filters.


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