Mongoose - using Populate on an array of ObjectId

Question

I've got a schema that looks a bit like:

var conversationSchema = new Schema({
    created: { type: Date, default: Date.now },
    updated: { type: Date, default: Date.now },
    recipients: { type: [Schema.ObjectId], ref: 'User' },
    messages: [ conversationMessageSchema ]
});

So my recipients collection, is a collection of object id's referencing my user schema / collection.

I need to populate these on query, so i'm trying this:

Conversation.findOne({ _id: myConversationId})
.populate('user')
.run(function(err, conversation){
    //do stuff
});

But obviously 'user' isn't populating...

Is there a way I can do this?

jackdbernier · Accepted Answer · 2013-03-16 13:59:45Z

125

For anyone else coming across this question.. the OP's code has an error in the schema definition.. it should be:

var conversationSchema = new Schema({
    created: { type: Date, default: Date.now },
    updated: { type: Date, default: Date.now },
    recipients: [{ type: Schema.ObjectId, ref: 'User' }],
    messages: [ conversationMessageSchema ]
});
mongoose.model('Conversation', conversationSchema);

edited Mar 16, 2013 at 13:59

jackdbernier

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answered Nov 6, 2012 at 3:20

Duncan_m

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5 Comments

Khalid Bajwa Over a year ago

You sir just saved me a world of pain. tips hat

Gura Over a year ago

Good way ! but how can you do an array of unique object id? With no duplicate?

Muli Yulzary Over a year ago

{ type: Schema.ObjectId, ref: 'User' , unique: true }

Dev Yego Over a year ago

@MuliYulzary, I don't think that's right based on the docs right here. They claim it's not a validator but only helps in the creation of MongoDB indexes.

Sushil Over a year ago

not working. returning empty array. my mongoose v5.11.14

aaronheckmann · Accepted Answer · 2013-08-13 21:37:39Z

45

Use the name of the schema path instead of the collection name:

Conversation.findOne({ _id: myConversationId})
.populate('recipients') // <==
.exec(function(err, conversation){
    //do stuff
});

edited Aug 13, 2013 at 21:37

answered May 14, 2012 at 21:33

aaronheckmann

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1 Comment

Sushil Over a year ago

my mongoose v5.11.14

Rustamjon Kirgizbaev · Accepted Answer · 2024-07-12 10:30:14Z

1

In my case I was using NestJS and I had schema Prop like this:

  @Prop({
    type: [{ type: Types.ObjectId, ref: 'Question' }],
    select: false,
  })
  // This shouldn't necessarily be Question[] as typescript cries
  questions: Types.ObjectId[]

and changing this schema Prop to this resolved my issue:

  @Prop({
    type: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Question' }],
    select: false,
  })
  questions: mongoose.Schema.Types.ObjectId[]

answered Jul 12, 2024 at 10:30

Rustamjon Kirgizbaev

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Comments

WasiF · Accepted Answer · 2024-09-23 19:25:40Z

1

Player Schema

@Schema()
export class Player {
  @Prop({ required: true })
  firstName: string

  @Prop({ required: true })
  lastName: string
}

Team Schema

@Schema()
export class Team {
  @Prop({ required: true })
  name: string;

  @Prop({ type: [Types.ObjectId], ref: 'Player', required: true })
  players: Types.ObjectId[];
}

Earlier I was doing wrong like the following and unable to populate the list

@Prop({ type: [{ type: Types.ObjectId, ref: 'Player' }], required: true })
players: Types.ObjectId[];

This is how I managed to work this:

@Prop({ type: [Types.ObjectId], ref: 'Player', required: true })
players: Types.ObjectId[];

answered Sep 23, 2024 at 19:25

WasiF

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