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Supabase 是一个开源的 Firebase 替代方案。Supabase 建立在 PostgreSQL 之上,提供了强大的 SQL 查询功能,并能够与现有工具和框架进行简单的接口对接。 LangChain.js 支持使用 pgvector 扩展将 Supabase Postgres 数据库用作向量存储。有关更多信息,请参阅 Supabase 博客文章 本指南提供了使用 Supabase 向量存储的快速概述。有关所有 SupabaseVectorStore 功能和配置的详细文档,请参阅 API 参考

概述

集成细节

设置

要使用 Supabase 向量存储,您需要设置 Supabase 数据库并安装 @langchain/community 集成包。您还需要安装官方 @supabase/supabase-js SDK 作为对等依赖项。 本指南还将使用 OpenAI 嵌入,这需要您安装 @langchain/openai 集成包。如果您愿意,也可以使用 其他支持的嵌入模型
npm install @langchain/community @langchain/core @supabase/supabase-js @langchain/openai
创建数据库后,运行以下 SQL 以设置 pgvector 并创建必要的表和函数:
-- Enable the pgvector extension to work with embedding vectors
create extension vector;

-- Create a table to store your documents
create table documents (
  id bigserial primary key,
  content text, -- corresponds to Document.pageContent
  metadata jsonb, -- corresponds to Document.metadata
  embedding vector(1536) -- 1536 works for OpenAI embeddings, change if needed
);

-- Create a function to search for documents
create function match_documents (
  query_embedding vector(1536),
  match_count int DEFAULT null,
  filter jsonb DEFAULT '{}'
) returns table (
  id bigint,
  content text,
  metadata jsonb,
  embedding jsonb,
  similarity float
)
language plpgsql
as $$
#variable_conflict use_column
begin
  return query
  select
    id,
    content,
    metadata,
    (embedding::text)::jsonb as embedding,
    1 - (documents.embedding <=> query_embedding) as similarity
  from documents
  where metadata @> filter
  order by documents.embedding <=> query_embedding
  limit match_count;
end;
$$;

凭据

完成此操作后,设置 SUPABASE_PRIVATE_KEYSUPABASE_URL 环境变量:
process.env.SUPABASE_PRIVATE_KEY = "your-api-key";
process.env.SUPABASE_URL = "your-supabase-db-url";
如果您在本指南中使用 OpenAI 嵌入,您还需要设置您的 OpenAI 密钥:
process.env.OPENAI_API_KEY = "YOUR_API_KEY";
如果您想获取模型调用的自动跟踪,您还可以通过取消注释以下内容来设置您的 LangSmith API 密钥:
// process.env.LANGSMITH_TRACING="true"
// process.env.LANGSMITH_API_KEY="your-api-key"

实例化

import { SupabaseVectorStore } from "@langchain/community/vectorstores/supabase";
import { OpenAIEmbeddings } from "@langchain/openai";

import { createClient } from "@supabase/supabase-js";

const embeddings = new OpenAIEmbeddings({
  model: "text-embedding-3-small",
});

const supabaseClient = createClient(
  process.env.SUPABASE_URL,
  process.env.SUPABASE_PRIVATE_KEY
);

const vectorStore = new SupabaseVectorStore(embeddings, {
  client: supabaseClient,
  tableName: "documents",
  queryName: "match_documents",
});

管理向量存储

向向量存储添加项目

import type { Document } from "@langchain/core/documents";

const document1: Document = {
  pageContent: "The powerhouse of the cell is the mitochondria",
  metadata: { source: "https://example.com" }
};

const document2: Document = {
  pageContent: "Buildings are made out of brick",
  metadata: { source: "https://example.com" }
};

const document3: Document = {
  pageContent: "Mitochondria are made out of lipids",
  metadata: { source: "https://example.com" }
};

const document4: Document = {
  pageContent: "The 2024 Olympics are in Paris",
  metadata: { source: "https://example.com" }
}

const documents = [document1, document2, document3, document4];

await vectorStore.addDocuments(documents, { ids: ["1", "2", "3", "4"] });
[ 1, 2, 3, 4 ]

从向量存储删除项目

await vectorStore.delete({ ids: ["4"] });

查询向量存储

一旦您的向量存储创建完毕并添加了相关文档,您很可能希望在运行链或代理期间对其进行查询。

直接查询

执行简单的相似性搜索可以按如下方式完成:
const filter = { source: "https://example.com" };

const similaritySearchResults = await vectorStore.similaritySearch("biology", 2, filter);

for (const doc of similaritySearchResults) {
  console.log(`* ${doc.pageContent} [${JSON.stringify(doc.metadata, null)}]`);
}
* The powerhouse of the cell is the mitochondria [{"source":"https://example.com"}]
* Mitochondria are made out of lipids [{"source":"https://example.com"}]
如果您想执行相似性搜索并接收相应的分数,您可以运行:
const similaritySearchWithScoreResults = await vectorStore.similaritySearchWithScore("biology", 2, filter)

for (const [doc, score] of similaritySearchWithScoreResults) {
  console.log(`* [SIM=${score.toFixed(3)}] ${doc.pageContent} [${JSON.stringify(doc.metadata)}]`);
}
* [SIM=0.165] The powerhouse of the cell is the mitochondria [{"source":"https://example.com"}]
* [SIM=0.148] Mitochondria are made out of lipids [{"source":"https://example.com"}]

元数据查询构建器过滤

您还可以使用类似于 Supabase JavaScript 库 工作方式的查询构建器风格的过滤,而不是传递对象。请注意,由于大多数过滤器属性都在元数据列中,您需要使用 Postgrest API 文档 中定义的箭头运算符(-> 用于整数或 ->> 用于文本)并指定属性的数据类型(例如,列应类似于 metadata->some_int_prop_name::int)。
import { SupabaseFilterRPCCall } from "@langchain/community/vectorstores/supabase";

const funcFilter: SupabaseFilterRPCCall = (rpc) =>
  rpc.filter("metadata->>source", "eq", "https://example.com");

const funcFilterSearchResults = await vectorStore.similaritySearch("biology", 2, funcFilter);

for (const doc of funcFilterSearchResults) {
  console.log(`* ${doc.pageContent} [${JSON.stringify(doc.metadata, null)}]`);
}
* The powerhouse of the cell is the mitochondria [{"source":"https://example.com"}]
* Mitochondria are made out of lipids [{"source":"https://example.com"}]

通过转换为检索器进行查询

您还可以将向量存储转换为 检索器,以便在链中更轻松地使用。
const retriever = vectorStore.asRetriever({
  // Optional filter
  filter: filter,
  k: 2,
});
await retriever.invoke("biology");
[
  Document {
    pageContent: 'The powerhouse of the cell is the mitochondria',
    metadata: { source: 'https://example.com' },
    id: undefined
  },
  Document {
    pageContent: 'Mitochondria are made out of lipids',
    metadata: { source: 'https://example.com' },
    id: undefined
  }
]

用于检索增强生成的用法

有关如何将此向量存储用于检索增强生成 (RAG) 的指南,请参阅以下部分:

API 参考

有关所有 SupabaseVectorStore 功能和配置的详细文档,请参阅 API 参考