Query entries by nested collection elements in RavenDB - ravendb

Question

I'm new to RavenDB and I'm struggling with this simple (i guess) issue.
I have a Subscriber with a collection of Subscriptions. And I want to make search by Subscription's fields, and return related Subscriber.
Here are simplified class examples:
public class Subscriber
{
public string Email { get; set; }
public string Name { get; set; }
public string Phone { get; set; }
public List<Subscription> Subscriptions { get; set; }
}
public class Subscription
{
public Guid Id { get; set; }
public string EventType { get; set; }
}
I've tried to make an index, as it is said in RavenDB docs:
public class Subscriber_BySubscription : AbstractIndexCreationTask<Subscriber>
{
public Subscriber_BySubscription()
{
Map = subscribers => from subscriber in subscribers
from subscription in subscriber.Subscriptions
select new
{
subscription.EventType,
subscription.QueueName
};
}
}
But I'm not sure that this is what I need, since query by collection using Select and Contains doesn't work. Moreover, the code looks so ugly that I feel that this is not the way how it should be.
So, I'd like to query Subscriptions by EventType, and have corresponding Subscriber as a result. In LINQ it would look like this: subscribers.Where(x => x.Subscriptions.Select(c => c.EventType).Contains(myEventType))

Answer 1

Managed to do it. Here is the right index:
public class Subscriber_BySubscription : AbstractIndexCreationTask<Subscriber>
{
public class Result
{
public string EventType { get; set; }
}
public Subscriber_BySubscription()
{
Map = subscribers => from subscriber in subscribers
from subscription in subscriber.Subscriptions
select new
{
subscription.EventType
};
}
}
And that's how it should be used:
var results = uow.Session
.Query<Subscriber_BySubscription.Result, Subscriber_BySubscription>()
.Where(x => x.EventType == eventType)
.OfType<Subscriber>()
.ToList();