How to use datamapper to return table entries as a json formatted string? Hash[Page.all( :fields => [:id, :title] ).map{|p|[p.id,p.title]}].to_json DEBUG (0.000176) SELECT `id`, `title` FROM `pages` ORDER BY `id` > {"1":"page A","2":"page B"} Page.all( :fields => [:title] ).map(&:title).to_json DEBUG (0.000038) SELECT `title` FROM `pages` ORDER BY `id` > ["page A","page B"]