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C#使用Qdrant实现向量存储及检索

news 2025/7/7 7:57:22

1、背景

C#通过Semantic Kernel可以实现向量存储和检索，向量的存储方式有很多（InMemory、各种专门的向量数据库之类），本次实现以Qdrant向量数据库实现，其他的向量数据库都是一样的。

2、步骤

2.1、下载Qdrant数据库

可以参考如下的文章，进行下载：2025年Windows 11系统下Qdrant向量数据库安装与使用全指南
本机的环境是安装的1.14.1
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2.2、下载Ollama并下载模型

Ollama的安装教程网上很多，不在此赘述。
本地环境为：ollama的版本是：ollama version is 0.9.3
本地中模型有：
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2.3、下载package

因为需要使用到Ollama和Qdrant向量数据库，所以需要安装相应的package
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2.4、代码实现

安装完软件后，创建一个控制台程序，然后引入上面的包后，全部代码如下：


using Microsoft.Extensions.AI;
using Microsoft.Extensions.VectorData;
using Microsoft.SemanticKernel;
using Microsoft.SemanticKernel.Connectors.Qdrant;
using OllamaSharp;
using Qdrant.Client;var kernelBuilder = Kernel.CreateBuilder();//1、设置嵌入的模型
IEmbeddingGenerator<string, Embedding<float>> embeddingGenerator = new OllamaApiClient(new Uri("http://localhost:11434"),"all-minilm");
//2、QdrantClient默认使用的gRPC方式联系，因此端口只能是6334,。
//6333那个http的端口，无法使用
var vectorStore = new QdrantVectorStore(new QdrantClient("localhost",6334,false), ownsClient: true, new QdrantVectorStoreOptions
{EmbeddingGenerator = embeddingGenerator
});//3、创建一个collection，并进行初始化
var collection = vectorStore.GetCollection<ulong, Movie>("movies");
await collection.EnsureCollectionExistsAsync();//4、把数据进行初始化
//其中，我们是讲描述进行了向量化，并保存到向量数据库中
var movieData = new List<Movie>()
{new Movie{Key=0,Title="Lion King",Description="The Lion King is a classic Disney animated film that tells the story of a young lion named Simba who embarks on a journey to reclaim his throne as the king of the Pride Lands after the tragic death of his father."},new Movie{Key=1,Title="Inception",Description="Inception is a science fiction film directed by Christopher Nolan that follows a group of thieves who enter the dreams of their targets to steal information."},new Movie{Key=2,Title="The Matrix",Description="The Matrix is a science fiction film directed by the Wachowskis that follows a computer hacker named Neo who discovers that the world he lives in is a simulated reality created by machines."},new Movie{Key=3,Title="Shrek",Description="Shrek is an animated film that tells the story of an ogre named Shrek who embarks on a quest to rescue Princess Fiona from a dragon and bring her back to the kingdom of Duloc."}
};//5、将描述向量化，并保存到数据库中
foreach (var movie in movieData)
{movie.Vector = await embeddingGenerator.GenerateVectorAsync(movie.Description);await collection.UpsertAsync(movie);
}//6、以上，完成了数据的保存
//从本布开始，进行数据检索。先将查询条件进行向量化
var query = "A family friendly movie";
var queryEmbedding = await embeddingGenerator.GenerateVectorAsync(query);//7、在向量中查询数据
//SearchAsync方法的第二个参数是，希望能获取几个结果。现在是2个结果
var results = collection.SearchAsync<ReadOnlyMemory<float>>(queryEmbedding, 2);//8、将结果展示出来
await foreach (var result in results)
{Console.WriteLine($"Key: {result.Record.Key}, Text: {result.Record.Title}");
}Console.ReadLine();//定义数据类型
public class Movie
{[VectorStoreKey]public ulong Key { get; set; }//title和Description是payload[VectorStoreData]public string? Title { get; set; }[VectorStoreData]public string? Description { get; set; }[VectorStoreVector(384, DistanceFunction = DistanceFunction.CosineSimilarity, IndexKind = IndexKind.Hnsw)]public ReadOnlyMemory<float> Vector { get; set; }
}