Question

I’m running EF 4.2 CF and want to create indexes on certain columns in my POCO objects.

As an example lets say we have this employee class:

public class Employee
{
  public int EmployeeID { get; set; }
  public string EmployeeCode { get; set; }
  public string FirstName { get; set; }
  public string LastName { get; set; }
  public DateTime HireDate { get; set; }
}

We often do searches for employees by their EmployeeCode and since there are a lot of employees it would be nice to have that indexed for performance reasons.

Can we do this with fluent api somehow? or perhaps data annotations?

I know it is possible to execute sql commands something like this:

context.Database.ExecuteSqlCommand("CREATE INDEX IX_NAME ON ...");

I would very much like to avoid raw SQL like that.

i know this does not exist but looking for something along those lines:

class EmployeeConfiguration : EntityTypeConfiguration<Employee>
    {
        internal EmployeeConfiguration()
        {
            this.HasIndex(e => e.EmployeeCode)
                .HasIndex(e => e.FirstName)
                .HasIndex(e => e.LastName);
        }
    }

or maybe using System.ComponentModel.DataAnnotations the POCO could look like this (again i know this does not exist):

public class Employee
{
  public int EmployeeID { get; set; }
  [Indexed]
  public string EmployeeCode { get; set; }
  [Indexed]
  public string FirstName { get; set; }
  [Indexed]
  public string LastName { get; set; }
  public DateTime HireDate { get; set; }
}

Anyone have any ideas on how to do this, or if there are any plans to implement a way to do this, the code first way?

UPDATE: As mentioned in the answer by Robba, this feature is implemented in EF version 6.1

Answer 1

After Migrations was introduced in EF 4.3 you can now add indexes when modifying or creating a table. Here is an excerpt from the EF 4.3 Code-Based Migrations Walkthrough from the ADO.NET team blog

namespace MigrationsCodeDemo.Migrations
{
    using System.Data.Entity.Migrations;

    public partial class AddPostClass : DbMigration
    {
        public override void Up()
        {
            CreateTable(
                "Posts",
                c => new
                    {
                        PostId = c.Int(nullable: false, identity: true),
                        Title = c.String(maxLength: 200),
                        Content = c.String(),
                        BlogId = c.Int(nullable: false),
                    })
                .PrimaryKey(t => t.PostId)
                .ForeignKey("Blogs", t => t.BlogId, cascadeDelete: true)
                .Index(t => t.BlogId)
                .Index(p => p.Title, unique: true);

            AddColumn("Blogs", "Rating", c => c.Int(nullable: false, defaultValue: 3));
        }

        public override void Down()
        {
            DropIndex("Posts", new[] { "BlogId" });
            DropForeignKey("Posts", "BlogId", "Blogs");
            DropColumn("Blogs", "Rating");
            DropTable("Posts");
        }
    }
}

This is a nice strongly typed way to add the indexes, which was what i was looking for when i first posted the question.