Linq2SQL+Repository pattern: how to implement type related mapping

I have the Repository pattern implemented to access DB data through the Linq2Sql ORM:

public abstract class RepositoryBase<T, TDb> : IRepository<T>
    where T : IEntity
    where TDb : class, IDbEntity, new()
{
    protected RepositoryBase(IUnityContainer container)
    {
        _container = container;

        _context = _container.Resolve<CMCoreDataClassesDataContext>();
    }

    public IQueryable<T> GetAll()
    {
        return GetTable().Select(GetConverter());
    }

    protected abstract Table<TDb> GetTable();
    protected abstract Expression<Func<TDb, T>> GetConverter();

    protected CMCoreDataClassesDataContext Context { get { return _context; } }

    private readonly IUnityContainer _container;
    private readonly CMCoreDataClassesDataContext _context;
}

Here is an example of particular Repository implementation:

public class CustomerProductRepository
    : RepositoryBase<ICommonCustomerProduct, CMCoreDAL.DbData.CustomerProduct>
{
    protected override Table<CMCoreDAL.DbData.CustomerProduct> GetTable()
    {
        return Context.CustomerProducts;
    }

    protected override Expression<Func<CMCoreDAL.DbData.CustomerProduct, ICommonCustomerProduct>> GetConverter()
    {
        return dbEntity => dbEntity.ProdId == (int)ProductType.ProductTypeEnum.CommonProduct
                    ? new CommonCustomerProduct
                    {
                        UnityContainer = UnityContainer,
                        InstanceId = dbEntity.InstanceId,
                        CustomerId = dbEntity.CustomerID,
                        StatusCode = dbEntity.StatusCode,

                        DeviceLicenses = dbEntity.DeviceLicenses,
                        ServerLicenses = dbEntity.ServerLicenses,
                    }
                    : new SpecificCustomerProduct()
                    {
                        UnityContainer = UnityContainer,
                        InstanceId = dbEntity.InstanceId,
                        CustomerId = dbEntity.CustomerID,
                        StatusCode = dbEntity.StatusCode,

                        UserLicenses = dbEntity.DeviceLicenses,
                    }
         ;
    }

Here SpecificCustomerProduct is inherited from CommonCustomerProduct.

Presented source code shows how records from DB are mapped to different instances according to instance type. There are a lot of common fields for these classes and only few of them are different.

I have 2 concerns for this code:

1. Some duplications of assignment operations;

2. Low readability: in order to add few more concrete classes I need to make unreadable chain:

   return dbEntity => dbEntity.ProdId == iType1
                   ? new Type1
                   {
                       ... assignments
                   }
                   : 
                   {
                       dbEntity.ProdId == iType2
                       ? new Type2
                       {
                           ... assignments
                       }
                  开发者_C百科     : new Type3
                       {
                           ... assignments
                       }
                   }
   

Is there any better way to implement 'type-related' mapping with such pattern?

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Have you looked at LINQ to SQL's Inheritance mapping? It allows you to map different classes to a common table, using a database column (type discriminator) to determine which type of object to generate.