RavenDB Map-Reduce Example using .NET Client

Question

I\'m looking for an example of how to implement and use Map-Reduce within the RavenDB .NET Client.

I\'d like to apply it to a specific scenario: generating unique a

Answer 1

Here is how you can build an index for unique visitors:

public class Statistics_UniqueVisitors : AbstractIndexCreationTask
{
    public Statistics_UniqueVisitors()
    {
        Map = entries => from entry in entries
                         select new { entry.UserId, Count = 1 };
        Reduce = results => from result in results
                            group result by result.UserId into g
                            select new { UserId = g.Key, Count = g.Sum(x=>x.Count) };
    }
}

You can then query this using:

var numberOfUniqueVisitors = s.Query().Count();

For total count of visitors, you can use:

var numberOfVisitors = s.Query().Count();