Collection Exists Criteria in WCF Data Services

Question

I\'m trying to ask my OData service:

\"Give me all the Products that do not have a Category\"

with the Products and Category have a m2m relationship.

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Answer 1

My solution to this problem was to $expand the related field in the query, and then test if that field was empty or not...

   JArray _array = (JArray)main_table_object["some_related_field"];

   if (_array.Count > 0) 
      continue; 

.. this is in the context of queries from Windows 7 phone to a WCF service using JSON as the message format.