Mongoose Node Js Join two collections

Question

I am new to MEAN Stack and I am developing application using Node Js.

I have two collections say,

 var personSchema = Schema({ _id: Number, name: String, age: Number, stories: { type: Array, ref: 'Story' } }); var storySchema = Schema({ _creator: { type: Number }, story_id: String, fans: [{ type: Number }] }); var Story = mongoose.model('Story', storySchema); var Person = mongoose.model('Person', personSchema); 

In Person schema, the stories is a list of story_id which is an array of values. I need to list out all the persons data with their stories details also.

I have used, Person.find().populate("stories");
But it throws error,

{
  [CastError: Cast to ObjectId failed
    for value "26747261"
    at path "_id"
  ]
  message: 'Cast to ObjectId failed for value "26747261" at path "_id"',
    name: 'CastError',
    kind: 'ObjectId',
    value: 26747261,
    path: '_id',
    reason: undefined
}

Please help.

Answer 1

The reason you are getting the CastError is that you are not storing a list of story ids as you intended in the Person schema:

 var personSchema = Schema({
   ...
   stories : { type: Array, ref: 'Story' }
 });

Instead you should change it to:

 var personSchema = Schema({
   ...
   stories : [{ type: Schema.Types.ObjectId, ref: 'Story' }]
 });

Also note the following (from Mongoose's documentation on population)

ObjectId, Number, String, and Buffer are valid for use as refs.