RavenDB creating static index and query on dictionary - indexing

Question

I'm trying to create a static index where I want all documents where a key exists and has a value. The value itself is not important, only the key exists.
I'm exploring this example with dynamic fields:
https://ravendb.net/docs/article-page/2.5/csharp/client-api/advanced/dynamic-fields
... and although I'm getting the index to work, I'm not sure if the query I'm using is correct.
This is the sample class:
public class Result
{
public Dictionary<string, List<Data>> Results { get; set; }
}
The key in the dictionary is the ID of a user (for example "user/1") and the value is a list of data-objects. The so the json-structure looks like this:
{
"Results" :
{
"user/1": [{...}],
"user/2": [{...}],
}
}
The index I use is this:
public class Result_ByUserId : AbstractIndexCreationTask<Result>
{
public Result_ByUserId()
{
Map = res => from r in res
select new
{
_ = r.Results
.Select(d => CreateField(d.Key, d.Value))
};
}
}
My problem comes down to the query, as it assumes I want to look at a specific key and value.
var resultat = session.Advanced.DocumentQuery<Result>("Result/ByUserId ")
.WhereEquals("user/1", "") // How do I write a !isNullOrEmpty?
.ToList();
... which I don't want to do. I only want the results that has a key in which the value is not null or empty. Does anybody have any good tips?

Answer 1

What you can do is index a boolean flag depending on if the dictionary has a value or not and then query on that.
public class Result_ByUserId : AbstractIndexCreationTask<Result>
{
public Result_ByUserId()
{
Map = res => from r in res
select new
{
_ = r.Results
.Select(d => CreateField(d.Key, d.Value != null ? true : false, false, true))
};
}
}
The query can then be:
var resultat = session.Advanced.DocumentQuery<Result>("Result/ByUserId ")
.WhereEquals("user/1", true)
.ToList();
This will return any Result documents that has a Dictionary with a key of user/1 and a dictionary value that's not null.
Not sure it's the best way of doing it, but it worked for me...
Hope this helps!