How do I parse nested JSON object?

What ruby gems and/or DSLs are available for converting SQL records into JSON objects?

• I have some complicated SQL ( connected to SQL Server using TinyTDS) and I want to output JSON.  The trick is, several SQL records map to a single JSON object.  What the is absolute easiest way to do this?  ActiveRecord?  DataMapper?    Sequel? That is, given select id, title, detail from .... I want JSON  in the  form { id:"123"  , title:"hello", details:["world","mom","dad"] } or a ruby hash {:id=>1, :title=>"hello", :details=>["world", "mom", "dad"]} I would like this to be as lightweight as possible (i.e. minimal install and dependencies), and fast so it can run on the command line and just dump hashes or JSON hashes to a flat file. I also need it to be a bit more clever, so it can map select id, title, detail_id, detail_text, detail_label  from .... to {:id=>1, :title=>"hello",   :detail_ids => [321,322,323], :detail_texts=>["world", "mom", "dad"] , :detail_labels =>[a,b,c]} or perhaps a nested structure  {:id=>1, :title=>"hello", :details=>[ {id:321, text:"world", label:a] , {}, {} ] or some other suitable JSON object

• Answer:

  I'm not quite sure what you're asking but I'll do my best to answer the question I want you to ask. It's all going to come down to the queries, I guess.  There, it's either going to be an N+1 deal to nest all the details or a join. As for gems that will serialize JSON... You can do it yourself with the JSON gem: http://flori.github.com/json/ Sequel has a JSON serializer: http://sequel.rubyforge.org/rdoc-plugins/classes/Sequel/Plugins/JsonSerializer.html I'd probably skip ActiveRecord and DataMapper depending on how legacy your legacy database is and go with straight SQL executed within Sequel or TinyTDS.