Mongoose unique index on subdocument

Question

Let\'s say I have a simple schema:

var testSchema = new mongoose.Schema({
    map: { type: [ mongoose.Schema.Types.Mixed ], default: [] },
    ...possibly so         


        

Answer 1

Long story short: Mongo doesn't support unique indexes for subdocuments, although it allows creating them...

Answer 2

This comes up in google so I thought I'd add an alternative to using an index to achieve unique key constraint like functionality in subdocuments, hope that's OK.

I'm not terribly familiar with Mongoose so it's just a mongo console update:

var foo = { _id: 'some value' }; //Your new subdoc here

db.yourCollection.update(
{ '_id': 'your query here', 'myArray._id': { '$ne': foo._id } },
{ '$push': { myArray: { foo } })

With documents looking like:

{
  _id: '...',
  myArray: [{_id:'your schema here'}, {...}, ...]
}

The key being that you ensure update will not return a document to update (i.e. the find part) if your subdocument key already exists.

Answer 3

First objectId length in mongodb must be 24. Then you can turn off _id, and rename _id as id or others,and try $addToSet. Good luck.

CoffeeScript example:

FromSchema = new Schema(
  source: { type: String, trim: true }
  version: String
  { _id: false }//to trun off _id
)

VisitorSchema = new Schema(
  id: { type: String, unique: true, trim: true }
  uids: [ { type: Number, unique: true} ]
  from: [ FromSchema ]
)

//to update
Visitor.findOneAndUpdate(
  { id: idfa }
  { $addToSet: { uids: uid, from: { source: source, version: version } } }
  { upsert: true }
  (err, visitor) ->
    //do stuff