Using Entity framework features Part 1

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

namespace Arash.Core.Model
{
    [Table("EntityBase")]
    public abstract class EntityBase
    {
        // primitive
        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int EntityId
        {
            get;
            set;
        }

        [ForeignKey("EntityType")]
        public int EntityTypeId { get; set; }

        // navigation

        [ForeignKey("EntityTypeId")]
        public EntityType EntityType
        {
            get;
            set;
        }

        public EntityTypes EntityTypes
        {
            get
            {
                return (EntityTypes)EntityType.Id;
            }
            set
            {
                EntityTypeId = (int)EntityTypes;
            }
        }

        public virtual IEnumerable Tages { get; set; }
    }
}
}

in sample project we have a three projects in Domain layer project: Core,  Membership, Restaurant. in each project we have a Model as a sub namespace that populate our models. These model folders have many entity classes. This entity classes are same object tables!Really?

After complete all models, we should create a DataAccess project and all model references to it:

There is two concept for develop code first POCO classes in EF 4.1/2: develop a partial class and bind properties to field names in SQL table or put code first attributes top of mapped properties of a POCO class.I use attribute model without add any .edmx file to project

using System.Data.Entity;
using Arash.Core.Model;
using Arash.Membership.Model;
using Arash.Restaurant.Model;
using Paradiso.Infrastructure.Data;

namespace Arash.DataAccess
{
    public class ArashDbContext : DbContext, IDbContext
    {
        public ArashDbContext() : base("arashConnectionString") { }

        public DbSet Members { get; set; }
        public DbSet Roles { get; set; }
        public DbSet Users { get; set; }
        public DbSet Jobs { get; set; }
        public DbSet EntityBases { get; set; }
        public DbSet EntityType { get; set; }
        public DbSet Tages { get; set; }
        public DbSet TagEntities { get; set; }
        public DbSet Coffeeshops { get; set; }

        public new IDbSet Set() where T : class
        {
            return base.Set();
        }

        public Database Query
        {
            get { return this.Database; }
        }

        public IDbSet GetDbSet() where T : class
        {
            return null;
        }

        public Database Db
        {
            get { return this.Database; }
        }
    }
}

So We making a new structure of model for domain layer and  data access layer. We could add a class as data initialize object to Db. For this:

sing System.Collections.Generic;
using System.Data.Entity;
using System.Data.Entity.Validation;
using System.Linq;
using Arash.Core.Model;
using Arash.DataAccess;

namespace Arash.DataAccess
{
    public class ArashDbContextInitializer : DropCreateDatabaseAlways
    {
        protected override void Seed(ArashDbContext context)
        {
            #region entity type
            new List
            {
                new EntityType {
                    Name = "Coffeeshop"
                },
                new EntityType {
                    Name = "bar"
                }
            }.ForEach(m => context.EntityType.Add(m));
            #endregion

            try
            {
                context.SaveChanges();
            }
            catch (DbEntityValidationException e)
            {
                var ex = e.EntityValidationErrors.ToList();
            }

            base.Seed(context);
        }
    }
}

Concludion:

We used EF 4.1/2 with code first concept for separating model projects. With these approach we can add a new models without change old assemblies or old domain projects

Please read Part 2 for using these approach for using in Service(Bussiness) layer