Document HasColumnOrder

Fixes #3469

entity-framework/core/modeling/entity-properties.md

@@ -201,3 +201,24 @@ You can set an arbitrary text comment that gets set on the database column, allo
 [!code-csharp[Main](../../../samples/core/Modeling/EntityProperties/FluentAPI/ColumnComment.cs?name=ColumnComment&highlight=5)]
 
 ***
+
+## Column order
+
+> [!NOTE]
+> This feature was introduced in EF Core 6.0.
+
+By default when creating a table with [Migrations](../managing-schemas/migrations/index.md), EF Core orders primary key columns first, followed by properties of the entity type and owned types, and finally properties from base types. You can, however, specify a different column order:
+
+### [Data Annotations](#tab/data-annotations)
+
+[!code-csharp[](../../../samples/core/Modeling/EntityProperties/DataAnnotations/ColumnOrder.cs#snippet_ColumnAttribute)]
+
+The Fluent API can be used to override ordering made with attributes, including resolving any conflicts when attributes on different properties specify the same order number.
+
+### [Fluent API](#tab/fluent-api)
+
+[!code-csharp[](../../../samples/core/Modeling/EntityProperties/FluentAPI/ColumnOrder.cs#snippet_HasColumnOrder)]
+
+***
+
+Note that, in the general case, most databases only support ordering columns when the table is created. This means that the column order attribute cannot be used to re-order columns in an existing table.

samples/core/Miscellaneous/NewInEFCore6/ColumnOrderSample.cs

@@ -111,7 +111,6 @@ public class Address
 
     public static class UsingModelBuilder
     {
-        #region WithOrdering
         public class EntityBase
         {
             public int Id { get; set; }
@@ -139,7 +138,6 @@ public class Address
             public string City { get; set; }
             public string Postcode { get; set; }
         }
-        #endregion
     }
 
     public class EmployeeContext : DbContext

samples/core/Modeling/EntityProperties/DataAnnotations/ColumnOrder.cs

@@ -0,0 +1,33 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+
+namespace EFModeling.EntityProperties.DataAnnotations.ColumnOrder
+{
+    internal class MyContext : DbContext
+    {
+        public DbSet<Employee> Employees { get; set; }
+    }
+
+    #region snippet_ColumnAttribute
+    public class EntityBase
+    {
+        [Column(Order = 0)]
+        public int Id { get; set; }
+    }
+
+    public class PersonBase : EntityBase
+    {
+        [Column(Order = 1)]
+        public string FirstName { get; set; }
+
+        [Column(Order = 2)]
+        public string LastName { get; set; }
+    }
+
+    public class Employee : PersonBase
+    {
+        public string Department { get; set; }
+        public decimal AnnualSalary { get; set; }
+    }
+    #endregion
+}

samples/core/Modeling/EntityProperties/FluentAPI/ColumnOrder.cs

@@ -0,0 +1,43 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace EFModeling.EntityProperties.FluentAPI.ColumnOrder
+{
+    internal class MyContext : DbContext
+    {
+        public DbSet<Employee> Employees { get; set; }
+
+        #region snippet_HasColumnOrder
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<Employee>(x =>
+            {
+                x.Property(b => b.Id)
+                    .HasColumnOrder(0);
+
+                x.Property(b => b.FirstName)
+                    .HasColumnOrder(1);
+
+                x.Property(b => b.LastName)
+                    .HasColumnOrder(2);
+            });
+        }
+        #endregion
+    }
+
+    public class EntityBase
+    {
+        public int Id { get; set; }
+    }
+
+    public class PersonBase : EntityBase
+    {
+        public string FirstName { get; set; }
+        public string LastName { get; set; }
+    }
+
+    public class Employee : PersonBase
+    {
+        public string Department { get; set; }
+        public decimal AnnualSalary { get; set; }
+    }
+}