Check out example codes for "mongo object references in mongoose". It will help you in understanding the concepts better.

Code Example 1

User = new Schema({
    places:[{type: Schema.Types.ObjectId, ref:'Place'}],
    shouts:[{type: Schema.Types.ObjectId, ref:'Shout'}]
});
Place = new Schema({
    name:String,
    description:String,
});
Shout = new Schema({
    content:String,
});

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