Mongoose multi update

Question

I want to update multiple docs with different values.

My Database looks something like this.

[
    {
        \"_id\": 1,
        \"value\": 50
    },
            


        

Answer 1

First of all your update() query is not ok..

See documentation for this here

Model.update(conditions, update, options, callback);

Suppose your current db model contains docs like this (as you described in question as well):

[
    {
        "_id": 1,
        "value": 50
    },
    {
        "_id": 2,
        "value": 100
   }
];

and you've below array which contains objects (i.e., docs) to be modified with current db's docs to like this:

idsArray: [
    {
        "_id": 1,
        "value": 4
    },
    {
        "_id": 2,
        "value": 27
    }
];

From my experience with mongodb & mongoose, i don't think you can update all docs with single line query (that's you're trying to do).. (P.S. I don't know about that so I am not sure to this..)

But to make your code work, you will be doing something like this:

Idea: Loop over each doc in docs i.e, idsArray and call update() over it..

So, Here's code to this:

idsArray.forEach(function(obj) {
    Model.update({_id: obj._id}, {$set: {value: obj.value}});
});

In above code, I am supposing you've _id values in db docs as they 're written above (i.e, "_id": 1).. But if they're like this "_id": ObjectId('1')

[
  {
    "_id": ObjectId('1'),
    "value": 50
  },
  .....
  .....
]

then you'll be need to convert _id to ObjectId(obj._id) in update() query.. so for that you'll be doing like this.

var ObjectId = require('mongodb').ObjectID;

idsArray.forEach(function(obj) {
   Model.update({_id: ObjectId(obj._id)}, {$set: {value: obj.value}});
});

P.S. Just confirm it (i.e., _id) before go forward..

Hope this helps.

Cheers,