Question

I’m trying to use the TransformResults feature, and I can’t get it to work. I’m not totally sure I understand this feature, perhaps there is another way to solve this problem. What I want is just the Id from the Order and the email addesses from the Customer and the Entrepreneur. I am happy for all tips that can take me in the right direction. Here is my code.

Document

public class OrderDocument

    public string Id {get; set }

    public EntrepreneurInfo EntrepreneurInfo { get; set; }

    public CustomerInfo CustomerInfo { get; set; }

    public OrderStatus CurrentOrderStatus { get; set; }
}

Info classes

public class EntrepreneurInfo
{
    public string EntrepreneurDocumentId { get; set; }

    public string Number { get; set; }

    public string Name { get; set; }
}

public class CustomerInfo
{
    public string CustomerDocumentId { get; set; }

    public string Number { get; set; }

    public string Name { get; set; }
}

The info classes are just subsets of a Customer and Entrepreneur documents respectively.
The Customer and Entrepreneur documents inherits from a base class ( AbstractOrganizationDocument) that has the EmailAddress property.

My Index

public class OrdersApprovedBroadcastingData : 
    AbstractIndexCreationTask<OrderDocument, OrdersApprovedBroadcastingData.ReduceResult>
{
    public OrdersApprovedBroadcastingData()
    {
        this.Map = docs => from d in docs 
                           where d.CurrentOrderStatus == OrderStatus.Approved 
                            select new
                            {
                                Id = d.Id,
                                CustomerId = d.CustomerInfo.CustomerDocumentId,
                                EntrepreneurId = d.EntrepreneurInfo.EntrepreneurDocumentId
                            };

        this.TransformResults = (db, orders) => from o in orders
                let customer = db.Load<CustomerDocument>(o.CustomerId)
                let entrepreneur = db.Load<EntrepreneurDocument>(o.EntrepreneurId)
                select
                    new 
                        {
                            o.Id,
                            o.CustomerId,
                            CustomerEmail = customer.EmailAddress,
                            o.EntrepreneurId,
                            EntrepreneurEmail = entrepreneur.EmailAddress
                        };
    }

    public class ReduceResult
    {
        public string Id { get; set; }

        public string CustomerId { get; set; }

        public string CustomerEmail { get; set; }

        public string EntrepreneurId { get; set; }

        public string EntrepreneurEmail { get; set; }
    }
}

If I look at the result of this Index in Raven Studio I get null values for all fields except the Id. And finally here is my query.

Query

        var items =
            this.documentSession.Query<OrdersApprovedBroadcastingData.ReduceResult, OrdersApprovedBroadcastingData>()
                .Select(x => new OrdersToBroadcastListItem
                    {
                        Id = x.Id,
                        CustomerEmailAddress = x.CustomerEmail,
                        EntrepreneurEmailAddress = x.EntrepreneurEmail
                    }).ToList();

Answer 1

Change your index to:

public class OrdersApprovedBroadcastingData : AbstractIndexCreationTask<OrderDocument>
{
  public OrdersApprovedBroadcastingData()
  {
    Map = docs => from d in docs
                  where d.CurrentOrderStatus == OrderStatus.Approved
                  select new
                  {
                  };

    TransformResults = (db, orders) =>
      from o in orders
      let customer = db.Load<CustomerDocument>(o.CustomerInfo.CustomerDocumentId)
      let entrepreneur = db.Load<EntrepreneurDocument>(o.EntrepreneurInfo.EntrepreneurDocumentId)
      select new
        {
          o.Id,
          CustomerEmailAddress = customer.EmailAddress,
          EntrepreneurEmailAddress = entrepreneur.EmailAddress
        };
  }
}

Your result class can simply be the final form of the projection, you don’t need the intermediate step:

public class Result
{
  public string Id { get; set; }
  public string CustomerEmailAddress { get; set; }
  public string EntrepreneurEmailAddress { get; set; }
}

You don’t have to nest this class in the index if you don’t want to. It doesn’t matter either way. You can query either with:

var items = session.Query<Result, OrdersApprovedBroadcastingData>();

Or with

var items = session.Query<OrderDocument, OrdersApprovedBroadcastingData>().As<Result>();

Though, with the first way, the convention tends to be to nest the result class, so really it would be

var items = session.Query<OrderDocument.Result, OrdersApprovedBroadcastingData>();

Note in the index map, I am not including any properties at all. None are required for what you asked. However, if you want to add a Where or OrderBy clause to your query, any fields you might want to filter or sort on should be put in there.

One last thing – the convention you’re using of OrderDocument, CustomerDocument, EntrepreneurDocument, is a bit strange. The usual convention is just Order, Customer, Entrepreneur. Think of your documents as the persisted form of the entities themselves. The convention you are using will work, it’s just not the one usually used.