How To Count Associated Entities Without Fetching Them In Entity Framework

Question

I\'ve been wondering about this one for a while now, so I thought it would be worth using my first Stack Overflow post to ask about it.

Imagine I have a discussion with

Answer 1

If you are using Entity Framework 4.1 or later, you can use:

var discussion = _repository.GetDiscussionCategory(id);

// Count how many messages the discussion has 
var messageCount = context.Entry(discussion)
                      .Collection(d => d.Messages)
                      .Query()
                      .Count();

Source: http://msdn.microsoft.com/en-US/data/jj574232