Question

I have a document in RavenDB that looks looks like:

{
    "ItemId": 1,
    "Title": "Villa
}

With the following metadata:

Raven-Clr-Type: MyNamespace.Item, MyNamespace
Raven-Entity-Name: Doelkaarten

So I serialized with a type MyNamespace.Item, but gave it my own Raven-Entity-Name, so it get its own collection.

In my code I define an index:

public class DoelkaartenIndex : AbstractIndexCreationTask<Item>
{
    public DoelkaartenIndex()
    {
        // MetadataFor(doc)["Raven-Entity-Name"].ToString() == "Doelkaarten"
        Map = items => from item in items
                       where MetadataFor(item)["Raven-Entity-Name"].ToString() == "Doelkaarten"
                       select new {Id = item.ItemId, Name = item.Title};
    }
}

In the Index it is translated in the “Maps” field to:

docs.Items
.Where(item => item["@metadata"]["Raven-Entity-Name"].ToString() == "Doelkaarten")
.Select(item => new {Id = item.ItemId, Name = item.Title})

A query on the index never gives results.

If the Maps field is manually changed to the code below it works…

from doc in docs
where doc["@metadata"]["Raven-Entity-Name"] == "Doelkaarten"
select new { Id = doc.ItemId, Name=doc.Title };

How is it possible to define in code the index that gives the required result?

RavenDB used: RavenHQ, Build #961

UPDATE:

What I’m doing is the following: I want to use SharePoint as a CMS, and use RavenDB as a ready-only replication of the SharePoint list data. I created a tool to sync from SharePoint lists to RavenDB. I have a generic type Item that I create from a SharePoint list item and that I serialize into RavenDB. So all my docs are of type Item. But they come from different lists with different properties, so I want to be able to differentiate. You propose to differentiate on an additional property, this would perfectly work. But then I will see all list items from all lists in one big Items collection… What would you think to be the best approach to this problem? Or just live with it? I want to use the indexes to create projections from all data in an Item to the actual data that I need.

Answer 1

You can’t easily change the name of a collection this way. The server-side will use the Raven-Entity-Name metadata, but the client side will determine the collection name via the conventions registered with the document store. The default convention being to use the type name of the entity.

You can provide your own custom convention by assigning a new function to DocumentStore.Conventions.FindTypeTagName – but it would probably be cumbersome to do that for every entity. You could create a custom attribute to apply to your entities and then write the function to look for and understand that attribute.

Really the simplest way is just to call your entity Doelkaarten instead of Item.

Regarding why the change in indexing works – it’s not because of the switch in linq syntax. It’s because you said from doc in docs instead of from doc in docs.Items. You probably could have done from doc in docs.Doelkaartens instead of using the where clause. They are equivalent. See this page in the docs for further examples.