RavenDB index with map reduce distinct [closed]

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 9 years ago.

I have a slightly complex index that I need over a RavenDB document

given this document definition like:

public class PriceDocument
{
    public string Id { get; set; }
    public Guid PriceId { get; set; }
    public decimal Price { get; set; }
    public DateTime? PricingDate { get; set; }
    public string Source { get; set; }
    public int Version { get; set; }    
}

I need to get all the products for a given productId (I can do that when I query) that are unique by PricingDate (latest) and Source

So given the following data:

var priceDocument = new PriceDocument  {
    Price = 1m,
    Id = productId + "/1",
    PricingDate = new DateTime(2011, 4, 1, 8, 0, 0),
    PriceId = productId,
    Source = "Bloomberg",
    Version = 1   
};

var priceDocument1 = new PriceDocument {
    Price = 1m,
    Id = productId + "/2",
    PricingDate = new DateTime(2011, 4, 1,9,0,0),
    PriceId = productId,
    Source = "Bloomberg", 
    Version = 1
};

I should get as a result priceDocument1, since its latest.

So far I have an index defined like this:

Map = docs => 
    from priceDocument in docs
    select new {
        PricingDate = priceDocument.PricingDate, 
        PricingSource = priceDocument.Source,
        Price = priceDocument.Price,
        PriceId = priceDocument.PriceId
    };

Reduce = results => 
    from result in results
    group result by new { result.PricingDate, result.Source } into price
    select new {
        PricingDate = price.Max(p => price.Key.PricingDate),
        PricingSource = price.Key.Source,
    };

But it doesnt work at run time, I'm getting an AbstractIndexingExecuter||8||Failed to index documents for index (my index name)

I've recreated this sample in a separate project and I can see that in stats in Raven Stud开发者_Go百科io that I get the error:

Cannot implicitly convert type 'System.DateTimeOffset' to 'int' changed the DateTime? to DateTime

And no luck.

I switched from using the date to use the I can rely on it incrementing so now the index looks like this:

Map = docs => 
    from priceDocument in docs
    select new {
        PricingDate = priceDocument.PricingDate,
        PricingSource = priceDocument.Source,
        ProductId = priceDocument.ProductId,
        ProductVersion = priceDocument.Version
    };

Reduce = results => 
    from result in results
    group result by new {
        result.PriceId,
        result.PricingDate,
        result.Source,
        result.Version
    } into price
    select new {
        PricingDate = price.Key.PricingDate,
        PricingSource = price.Key,
        ProductVersion = price.Max(p=> price.Key.Version)
    };

Now that throws no errors, however it also gives no results.

---

It should probably be this:

   PricingDate = price.Max(p => (DateTimeOffset)price.Key.PricingDate)

But what you want doesn't require a map reduce index. You can get that by just using:

session.Query<PriceDocument>()
       .Where(x=>x.ProduceId == prodId)
       .OrderByDescending(x=>x.PriceDate)
       .FirstOrDefault();

The reason your Map/Reduce index doesn't work is that you have different outputs for the map & reduce functions.

---

Trying changing this line in the Reduce part of the index, from

PricingDate = price.Max(p => price.Key.PricingDate)

to

PricingDate = price.Max(p => (int)price.Key.PricingDate)