Creating Indexes via Data Annotations with Entity Framework 5.0

CompositeDatabaseInitializer.cs

using System.Collections.Generic;
using System.Data.Entity;

public class CompositeDatabaseInitializer<T> : IDatabaseInitializer<T> where T : DbContext
{
    private readonly List<IDatabaseInitializer<T>> initializers;

    public CompositeDatabaseInitializer(params IDatabaseInitializer<T>[] databaseInitializers)
    {
        this.initializers = new List<IDatabaseInitializer<T>>();
        this.initializers.AddRange(databaseInitializers);
    }

    public void InitializeDatabase(T context)
    {
        foreach (var databaseInitializer in this.initializers)
        {
            databaseInitializer.InitializeDatabase(context);
        }
    }

    public void AddInitializer(IDatabaseInitializer<T> databaseInitializer)
    {
        this.initializers.Add(databaseInitializer);
    }

    public void RemoveInitializer(IDatabaseInitializer<T> databaseInitializer)
    {
        this.initializers.Remove(databaseInitializer);
    }
}

Customer.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

public class Customer
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid Id { get; set; }

    [Index("NameIndex", unique: true)]
    [MaxLength(128)]
    public string Name { get; set; }
}

CustomerTable.cs

[Table("Clients")]
public class Customer
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid Id { get; set; }

    [Index("NameIndex", unique: true)]
    [MaxLength(128)]
    [Column("CustomerName")]
    public string Name { get; set; }
}

IndexAttribute.cs

using System;

[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
public class IndexAttribute : Attribute
{
    public IndexAttribute(string name, bool unique = false)
    {
        this.Name = name;
        this.IsUnique = unique;
    }

    public string Name { get; private set; }

    public bool IsUnique { get; private set; }
}

IndexInitializer.cs

using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Linq;
using System.Reflection;

public class IndexInitializer<T> : IDatabaseInitializer<T> where T : DbContext
{
    private const string CreateIndexQueryTemplate = "CREATE {unique} INDEX {indexName} ON {tableName} ({columnName})";

    public void InitializeDatabase(T context)
    {
        const BindingFlags PublicInstance = BindingFlags.Public | BindingFlags.Instance;

        foreach (var dataSetProperty in typeof(T).GetProperties(PublicInstance).Where(
            p => p.PropertyType.Name == typeof(DbSet<>).Name))
        {
            var entityType = dataSetProperty.PropertyType.GetGenericArguments().Single();

            TableAttribute[] tableAttributes = (TableAttribute[])entityType.GetCustomAttributes(typeof(TableAttribute), false);

            foreach (var property in entityType.GetProperties(PublicInstance))
            {
                IndexAttribute[] indexAttributes = (IndexAttribute[])property.GetCustomAttributes(typeof(IndexAttribute), false);
                NotMappedAttribute[] notMappedAttributes = (NotMappedAttribute[])property.GetCustomAttributes(typeof(NotMappedAttribute), false);
                if (indexAttributes.Length > 0 && notMappedAttributes.Length == 0)
                {
                    ColumnAttribute[] columnAttributes = (ColumnAttribute[])property.GetCustomAttributes(typeof(ColumnAttribute), false);

                    foreach (var indexAttribute in indexAttributes)
                    {
                        string indexName = indexAttribute.Name;
                        string tableName = tableAttributes.Length != 0 ? tableAttributes[0].Name : dataSetProperty.Name;
                        string columnName = columnAttributes.Length != 0 ? columnAttributes[0].Name : property.Name;
                        string query = CreateIndexQueryTemplate.Replace("{indexName}", indexName)
                            .Replace("{tableName}", tableName)
                            .Replace("{columnName}", columnName)
                            .Replace("{unique}", indexAttribute.IsUnique ? "UNIQUE" : string.Empty);

                        context.Database.CreateIfNotExists();

                        context.Database.ExecuteSqlCommand(query);
                    }
                }
            }
        }
    }
}