gistfile1.rb

          query = Hash.new

          if @bid_request[:geo][:dma].is_a? Fixnum
                # {$or:[ {field:{$in:[X]}} , {field:{$size:0}}]}
           query[:dma_codes] = {:$in => [@bid_request[:geo][:dma]]}
#           query[:dma_codes] = { :$size => 0 }
#          query[:dma_codes] = {:$or => [{:$in=>[@bid_request[:geo][:dma]]}, {:$size=>0}] }
#          query[:dma_codes] = {:$or => [{:$in => [@bid_request[:geo][:dma]]}, {:$size=>0}]}
#          query[:dma_codes] = {:$in => [{:$in=>[@bid_request[:geo][:dma]]}], :$size=>0 }
#         query[:dma_codes] = {"$or" => [ {'dma_codes' => { "$in" => [X]}}, {'dma_codes' => { "$size" => 0}}]}
          end

          # Gender
          # 0 => Both/Neither,  1 => Male,  2 => Female
          case @bid_request[:demo][:gender]
            when 'M':
              query[:gender] = {:gender => 1}
            when 'F':
              query[:gender] = {:gender => 2}
            else
              query.delete(:gender)
          end