array update in mongoDB - node.js

Question

I've got mongoose schema like this:
var mySchema = new mongoose.Schema({
user: String,
photos: [{
url: String,
thumbnail: String,
time: Date,
mainPhoto: Boolean
}]
});
now, I'd like to make a "setMainPhoto" function - for given id - set mainPhoto flag to true, and set it to false for other photos.
There is a document like this:
{
"_id": {
"$oid": "56269dea07a455920a21bca7"
},
"user": "someUser",
"photos": [
{
"time": {
"$date": "2015-05-25T08:37:56.000Z"
},
"thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
"url": "https://s3-eu-west-1.amazonaws.com/...jpg",
"_id": {
"$oid": "56269e2e07a455920a21bcab"
},
"mainPhoto": false
},
{
"time": {
"$date": "2015-05-25T09:27:17.000Z"
},
"thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
"url": "https://s3-eu-west-1.amazonaws.com/...jpg",
"_id": {
"$oid": "56269e3507a455920a21bcae"
},
"mainPhoto": true
},
{
"time": {
"$date": "2015-05-25T09:27:17.000Z"
},
"thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
"url": "https://s3-eu-west-1.amazonaws.com/...jpg",
"_id": {
"$oid": "56269e3507a455920a21bcaf"
},
"mainPhoto": false
}
]}
I'm trying to do this with mongoose save function:
var myModel = mongoose.model('myCollection', mySchema);
myModel.find({user:params.user,_id:params.documentId}, function(err,data){
var newMyModel = new myModel(data[0]);
for(var i=0; i<newMyModel.photos.length; i++){
if(newMyModel.photos[i]._id == params.photoId){
newMyModel.photos[i].mainPhoto = true;
}else{
newMyModel.photos[i].mainPhoto = false;
}
}
return newTrack.save(function(err,results){
console.log(err,results);
return cb(err,results);
});
});
but I'm getting an error:
'E11000 duplicate key error index: xx.$_id_ dup key: { : ObjectId(\'56269dea07a455920a21bca7\') }',
apart from the fact I feel there is a better way to do this

Answer 1

You may want to try a conditional type of update operation that first updates the documents based on the given criteria using the .update() method with a callback, and then do the other update in the callback for documents that do not satisfy the given criteria. For example, you could restructure this as:
var Model = mongoose.model('myCollection', mySchema);
Model.update(
{
"_id": params.documentId,
"user": params.user,
"photos.mainPhoto": true
},
{
"$set": {
"photos.$.mainPhoto": false
}
},
function(err, numAffected) {
Model.update(
{
"_id": params.documentId,
"user": params.user,
"photos._id": params.photoId /* criteria for setting the updating the documents to true */
},
{
"$set": {
"photos.$.mainPhoto": true
}
},
function(err, numAffected) {
/* Update complete. */
}
)
}
)