Proper way to create nested objects in mongo

Question

Proper way to create nested objects in mongo

I am trying to create an array of nested objects. I am following an example from a book that does the following:

      // Creates the Schema for the Features object (mimics ESRI)
      var Phone = new Schema({
          number: { type: Number, required: false },
          ...
          personId: {type: Schema.Types.ObjectId}
        }
      );

      // Creates the Schema for the Attachments object
      var Person = new Schema({   
         name: { type: String },  
         phones: [Phone]
        }
      );

  var Person = mongoose.model('Person', Person);

Which works just fine when storing multiple Phone #'s for a person. However I am not sure if there is a good/fast way to get a Phone object by _id. Since Phone is not a mongoose model you cannot go directly to Phone.findOne({...}); Right now I am stuck with getting a person by _id then looping over that persons phones and seeing if the id matches.

Then I stumbled upon this link: http://mongoosejs.com/docs/populate.html

Is one way more right than the other? Currently when I delete a person his/her phones go away as well. Not really sure that works with 'populate', seems like I would need to delete Person and Phones.

Anyone want to attempt to explain the differences?

Thanks in advance

node.js
mongoose

Answer 1

The general rule is that if you need to independently query Phones, then you should keep them in a separate collection and use populate to look them up from People when needed. Otherwise, embedding them is typically a better choice as it simplifies updates and deletion.

When using an embedded approach like you are now, note that Mongoose arrays provide an id method you can use to more easily look up an element by its _id value.

var phone = person.phones.id(id);