Added drop functions

Author: HaikAsatryan

Readme.md

@@ -15,6 +15,8 @@ features.
    enhancing security and balancing database load.
 3. **Natural Sorting**: Provides way to calculate natural sort compliant order for string, which can be used
    in `ORDER BY` clause. This is useful for sorting strings that contain numbers in a human-friendly way.
+4. **Schema Rollback Helpers**: Extension methods `DropRandomIdSequence` and `DropNaturalSortKeyFunction` simplify
+   cleanup in `Down` migrations.
 
 ## Installation
 
@@ -109,6 +111,8 @@ public partial class PgFunction : Migration
     /// <inheritdoc />
     protected override void Down(MigrationBuilder migrationBuilder)
     {
+        migrationBuilder.DropRandomIdSequence("animal", "id");
+         
         migrationBuilder.DropTable(
             name: "animal");
     }
@@ -138,6 +142,10 @@ substrings numerically.
         // Create the natural sort key function in PostgreSQL
         migrationBuilder.CreateNaturalSortKeyFunction();   
 
+        protected override void Down(MigrationBuilder migrationBuilder)
+           {
+               migrationBuilder.DropNaturalSortKeyFunction();        
+           }
         }
     }
     ```
@@ -154,6 +162,7 @@ substrings numerically.
         }
     }    
     ```
+
 When you query the entity, simply `ORDER BY AddressNaturalSortKey` to get true “natural” ordering in PostgreSQL.
 
 ## License

src/EFCore.PostgresExtensions/EFCore.PostgresExtensions.csproj

@@ -8,13 +8,13 @@
         <PackageReadmeFile>Readme.md</PackageReadmeFile>
         <Authors>Pandatech</Authors>
         <Copyright>MIT</Copyright>
-        <Version>5.1.0</Version>
+        <Version>5.1.1</Version>
         <PackageId>Pandatech.EFCore.PostgresExtensions</PackageId>
         <Title>Pandatech.EFCore.PostgresExtensions</Title>
         <PackageTags>Pandatech, library, EntityFrameworkCore, PostgreSQL, For Update, Lock, LockingSyntax, Bulk insert, BinaryCopy</PackageTags>
         <Description>The Pandatech.EFCore.PostgresExtensions library enriches Entity Framework Core applications with advanced PostgreSQL functionalities, starting with the ForUpdate locking syntax and BulkInsert function. Designed for seamless integration, this NuGet package aims to enhance the efficiency and capabilities of EF Core models when working with PostgreSQL, with the potential for further PostgreSQL-specific extensions.</Description>
         <RepositoryUrl>https://github.com/PandaTechAM/be-lib-efcore-postgres-extensions</RepositoryUrl>
-        <PackageReleaseNotes>Added support to generate unique index on encrypted columns</PackageReleaseNotes>
+        <PackageReleaseNotes>Added down function for natural sort key and random id sequence</PackageReleaseNotes>
     </PropertyGroup>
 
     <ItemGroup>

src/EFCore.PostgresExtensions/Extensions/MigrationBuilderExtensions.cs

@@ -40,6 +40,52 @@ CREATE UNIQUE INDEX {indexName}
 
       return migrationBuilder;
    }
+   
+   /// <summary>
+   /// Removes the random‑ID generator function *and* its backing sequence.
+   /// </summary>
+   public static void DropRandomIdSequence(this MigrationBuilder migrationBuilder,
+      string tableName,
+      string pkName)
+   {
+      var sequenceName = $"{tableName}_{pkName}_seq";
+      var functionName = $"{tableName}_random_id_generator";
+
+      var sql = $"""
+                 DO $$
+                 BEGIN
+                     -- drop function if it exists
+                     IF EXISTS (
+                         SELECT 1
+                         FROM pg_proc
+                         WHERE proname = '{functionName}'
+                     ) THEN
+                         DROP FUNCTION IF EXISTS {functionName}();
+                     END IF;
+
+                     -- drop sequence if it exists
+                     IF EXISTS (
+                         SELECT 1
+                         FROM pg_class
+                         WHERE relkind = 'S'
+                           AND relname = '{sequenceName}'
+                     ) THEN
+                         DROP SEQUENCE IF EXISTS {sequenceName};
+                     END IF;
+                 END
+                 $$;
+                 """;
+
+      migrationBuilder.Sql(sql);
+   }
+
+   /// <summary>
+   /// Removes the natural‑sort‑key function.
+   /// </summary>
+   public static void DropNaturalSortKeyFunction(this MigrationBuilder migrationBuilder)
+   {
+      migrationBuilder.Sql("DROP FUNCTION IF EXISTS get_natural_sort_key(TEXT);");
+   }
 
    public static MigrationBuilder CreateUniqueIndexOnEncryptedColumn(this MigrationBuilder migrationBuilder,
       string tableName,

test/PandaNuGet.Demo/PandaNuGet.Demo.csproj

@@ -10,10 +10,9 @@
     <ItemGroup>
         <PackageReference Include="Dapper" Version="2.1.66" />
         <PackageReference Include="EFCore.BulkExtensions.PostgreSql" Version="9.0.1" />
-        <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.3" />
-        <PackageReference Include="Pandatech.Crypto" Version="4.1.2" />
+        <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.4" />
         <PackageReference Include="Pandatech.EFCoreQueryMagic" Version="1.1.0" />
-        <PackageReference Include="Swashbuckle.AspNetCore" Version="8.0.0" />
+        <PackageReference Include="Swashbuckle.AspNetCore" Version="8.1.1" />
     </ItemGroup>
 
     <ItemGroup>

test/PandaNuGet.Demo/Services/GetByFirstBytesService.cs

@@ -3,7 +3,6 @@
 using PandaNuGet.Demo.Context;
 using PandaNuGet.Demo.Entities;
 using Pandatech.Crypto;
-using Pandatech.Crypto.Helpers;
 using PostgresDbContext = PandaNuGet.Demo.Context.PostgresDbContext;
 
 namespace PandaNuGet.Demo.Services;
@@ -81,12 +80,11 @@ public static IQueryable<T> WhereStartWithBytes<T>(this IQueryable<T> source,
 
       // MethodInfo for the substr method
       var methodInfo = typeof(PostgresDbContext).GetMethod(nameof(PostgresDbContext.substr),
-         new[]
-         {
-            typeof(byte[]),
+      [
+         typeof(byte[]),
             typeof(int),
             typeof(int)
-         });
+      ]);
 
       // Call to substr method
       var call = Expression.Call(

test/PandaNuGet.Tests/PandaNuGet.Tests.csproj

@@ -12,7 +12,7 @@
     <ItemGroup>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
         <PackageReference Include="xunit" Version="2.9.3" />
-        <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2">
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.1.0">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>