Added support for serial

Author: messieurMe

src/EfCore.Ydb/src/Metadata/Internal/YdbAnnotationNames.cs

@@ -0,0 +1,8 @@
+namespace EfCore.Ydb.Metadata.Internal;
+
+public static class YdbAnnotationNames
+{
+    public const string Prefix = "Ydb";
+
+    public const string Serial = Prefix + "Serial";
+}

src/EfCore.Ydb/src/Metadata/Internal/YdbAnnotationProvider.cs

@@ -1,12 +1,36 @@
+using System.Collections.Generic;
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 
 namespace EfCore.Ydb.Metadata.Internal;
 
 public class YdbAnnotationProvider : RelationalAnnotationProvider
 {
-    public YdbAnnotationProvider(
-        RelationalAnnotationProviderDependencies dependencies
-    ) : base(dependencies)
+    public YdbAnnotationProvider(RelationalAnnotationProviderDependencies dependencies) : base(dependencies)
     {
     }
+
+    public override IEnumerable<IAnnotation> For(IColumn column, bool designTime)
+    {
+        if (!designTime)
+        {
+            yield break;
+        }
+
+        // TODO: Add Yson here too?
+        if (column is JsonColumn)
+        {
+            yield break;
+        }
+
+        var property = column.PropertyMappings[0].Property;
+
+        if (property.ValueGenerated == ValueGenerated.OnAdd
+            && property.ClrType == typeof(int)
+            && property.FindTypeMapping()?.Converter == null)
+        {
+            yield return new Annotation(YdbAnnotationNames.Serial, true);
+        }
+    }
 }

src/EfCore.Ydb/src/Migrations/YdbMigrationsSqlGenerator.cs

@@ -1,3 +1,5 @@
+using System;
+using EfCore.Ydb.Metadata.Internal;
 using Microsoft.EntityFrameworkCore.Metadata;
 using Microsoft.EntityFrameworkCore.Migrations;
 using Microsoft.EntityFrameworkCore.Migrations.Operations;
@@ -46,7 +48,37 @@ protected override void Generate(
             EndStatement(builder, suppressTransaction: true);
         }
     }
-    
+
+    protected override void ColumnDefinition(
+        string? schema,
+        string table,
+        string name,
+        ColumnOperation operation,
+        IModel? model,
+        MigrationCommandListBuilder builder
+    )
+    {
+        var columnType = operation.ColumnType ?? GetColumnType(schema, table, name, operation, model)!;
+        var autoincrement = operation[YdbAnnotationNames.Serial] as bool?;
+
+        if (autoincrement == true)
+        {
+            columnType = columnType.ToLower() switch
+            {
+                "int32" => "SERIAL",
+                "int64" => "BIGSERIAL",
+                _ => throw new NotSupportedException("Serial column supported only for int32 and int64")
+            };
+        }
+
+        builder
+            .Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(name))
+            .Append(" ")
+            // TODO: Add DEFAULT logic somewhere here
+            .Append(columnType)
+            .Append(operation.IsNullable ? " NULL" : " NOT NULL");
+    }
+
     protected override void CreateTablePrimaryKeyConstraint(
         CreateTableOperation operation,
         IModel? model,