completed Dapper sample

Author: yorek

DotNet/Dapper/Model.cs

@@ -14,8 +14,7 @@ public class Post
     public int PostId { get; set; }
     public string Title { get; set; } = string.Empty;
     public string Content { get; set; } = string.Empty;
-    // We'll use SqlVector<float> to represent the SQL Server vector type when passing to SqlClient
-    public SqlVector<float>? Embedding { get; set; }
+    public float[]? Embedding { get; set; }
     public int BlogId { get; set; }
 }
 

DotNet/Dapper/Program.cs

@@ -8,15 +8,19 @@
 // Load .env
 Env.Load();
 
+// Update Dapper Type Handler to handle SqlVector<T>
+SqlMapper.AddTypeHandler(new VectorTypeHandler());
+
+// Get connection string from environment variable
 var connectionString = Environment.GetEnvironmentVariable("MSSQL");
 if (string.IsNullOrWhiteSpace(connectionString))
 {
     Console.WriteLine("Please set the MSSQL environment variable (for example in a .env file). Exiting.");
     return;
 }
 
+// Create SQL connection
 await using var connection = new SqlConnection(connectionString);
-await connection.OpenAsync();
 
 // Confirm database project objects exist
 var tableExists = await connection.ExecuteScalarAsync<int?>(
@@ -54,35 +58,34 @@
 {
     // compute embedding
     var vector = embeddingClient.GetEmbedding(np.Content);
-    var sqlVector = new SqlVector<float>(vector);
 
     // check if post exists for this blog
     var existingPostId = await connection.QuerySingleOrDefaultAsync<int?>(
         "SELECT PostId FROM dbo.Posts WHERE BlogId = @BlogId and Title = @Title",
-        new { BlogId = blogId, @Title = np.Title });
+        new { BlogId = blogId, Title = np.Title });
 
     if (existingPostId.HasValue)
     {
         await connection.ExecuteAsync(
             "UPDATE dbo.Posts SET Content = @Content, Embedding = @Embedding WHERE PostId = @PostId",
-            new { np.Content, Embedding = sqlVector, PostId = existingPostId.Value }
+            new { np.Content, Embedding = vector, PostId = existingPostId.Value }
         );
     }
     else
     {
         await connection.ExecuteAsync(
             "INSERT INTO dbo.Posts (Title, Content, Embedding, BlogId) VALUES (@Title, @Content, @Embedding, @BlogId)",
-            new { np.Title, np.Content, Embedding = sqlVector, BlogId = blogId }
+            new { np.Title, np.Content, Embedding = vector, BlogId = blogId }
         );
     }
 }
 
 // Query for similar posts
 Console.WriteLine("\n----------\n");
-string searchPhrase = "I want to use Azure SQL, EF Core and vectors in my app!";
+string searchPhrase = "I want to use Azure SQL, Dapper and vectors in my app!";
 Console.WriteLine($"Search phrase is: '{searchPhrase}'...");
 
-var queryVector = new SqlVector<float>(embeddingClient.GetEmbedding(searchPhrase));
+var queryVector = embeddingClient.GetEmbedding(searchPhrase);
 
 var sql = @"
 SELECT TOP (5) p.Title,

DotNet/Dapper/TypeHandler.cs

@@ -0,0 +1,18 @@
+using Microsoft.Data.SqlClient;
+using Dapper;
+using Microsoft.Data.SqlTypes;
+using Microsoft.Data;
+
+public class VectorTypeHandler: SqlMapper.TypeHandler<float[]>
+{
+    public override float[] Parse(object value)
+    {
+        return ((SqlVector<float>)value).Memory.ToArray();
+    }
+
+    public override void SetValue(System.Data.IDbDataParameter parameter, float[]? value)
+    {
+        parameter.Value = value is not null ? new SqlVector<float>(value) : DBNull.Value;
+        ((SqlParameter)parameter).SqlDbType = SqlDbTypeExtensions.Vector;
+    }
+}

DotNet/Dapper/content.json

@@ -5,10 +5,38 @@
   },
   {
     "Title": "Vectors with Azure SQL and Dapper",
-    "Content": "You can store vectors in Azure SQL and query them from Dapper by passing SqlVector parameters to Microsoft.Data.SqlClient."
+    "Content": "You can store vectors in Azure SQL and query them from Dapper by defining a type handler that uses the new SqlVector type from Microsoft.Data.SqlClient."
   },
   {
     "Title": "Dapper and vector search",
     "Content": "This sample shows how to use Dapper for vector-enabled queries against Azure SQL (vector column type)."
+  },
+  {
+    "Title": "SQL Server Best Practices",
+    "Content": "Here are some best practices for using SQL Server in your applications."
+  },
+  {
+    "Title": "Python and Flask",
+    "Content": "Learn how to build a web app using Python and Flask!"
+  },
+  {
+    "Title": "Django for REST APIs",
+    "Content": "Create a REST API using Django!"
+  },
+  {
+    "Title": "JavaScript for Beginners",
+    "Content": "Learn JavaScript from scratch!"
+  },
+  {
+    "Title": "Node vs Rust",
+    "Content": "Which one should you choose for your next project?"
+  },
+  {
+    "Title": "Pizza or Focaccia?",
+    "Content": "What's the difference between pizza and focaccia. Learn everything you need to know!"
+  },
+  {
+    "Title": "Chocolate Eggs for your next dessert",
+    "Content": "Try this delicious recipe for chocolate eggs!"
   }
 ]