gistfile1.txt

{
  "_id": {"$oid": "546396c27e12bd7eab000007"},
  "id": "43",
  "doe": "3BL",
  "buck": "C16",
  "birth_date": "2014-10-24 04:00:00 UTC",
  "kindled": 2,
  "survived": 2,
  "weights": [
    {
      "date": "2014-11-10 05:00:00 UTC",
      "data": [
        {
          "weight": 1.14,
          "count": 1,
          "id": "A",
          "notes": ""
        },
        {
          "weight": 1.1,
          "count": 1,
          "id": "B",
          "notes": ""
        }
      ]
    }
  ]
}

doc = { "weight": 1.2, "count": =, "id": "C", "notes": "another" }
    
What does adding the doc above to the end of the weights.data array look like ?

    litters.update( {id: "43" }, { "$push" =>  { ??? } } )

Where do I specify the weights.date so that it goes into the right one ?

SOLVED (in Ruby)

litters.update( {:id => params[:id], "weights.date" => date  }, { "$push" =>  { "weights.$.data" => data } } )

Mongo syntax (I think) is:

litters.update( {id: "43", "weights.date": ~the-date~ }, { "$push": { "weights.$.data": doc } } )