CODEWITHSUNDEEP
node.jsmongodbmongoose
andrei
andrei

Reputation: 8582

Getting data from multiple collections in mongodb

Let's say for example i have 2 collections Comments and Users.The comments include username and the comment and Users has username and avatar. When retrieving the comments i also want to display the avatars, how should i query the two collections ? My first thought was to get all the comments and then iterate though the usernames and query the user collection to get the avatars. Can i do this differently ? Using nodejs and mongoose

Upvotes: 2

Views: 6382

Answers (2)

Eve Freeman
Eve Freeman

Reputation: 33145

Populate is likely what you're looking for:

http://mongoosejs.com/docs/populate.html

Pasting some in here for posterity: ObjectIds can now refer to another document in a collection within our database and be populate()d when querying. An example is helpful:

var mongoose = require('mongoose')
 , Schema = mongoose.Schema

var PersonSchema = new Schema({
  name    : String
  , age     : Number
  , stories : [{ type: Schema.ObjectId, ref: 'Story' }]
});

var StorySchema = new Schema({
  _creator : { type: Schema.ObjectId, ref: 'Person' }
  , title    : String
  , fans     : [{ type: Schema.ObjectId, ref: 'Person' }]
});

var Story  = mongoose.model('Story', StorySchema);
var Person = mongoose.model('Person', PersonSchema);

Upvotes: 3

RStrad
RStrad

Reputation: 162

If I could comment I would as this may not be a full answer. But for me Database References and MongoDB Data Modeling and Rails are pretty good explanations on the topic in general.

But definitely what you are describing is what is discussed in the first link I sent.

Upvotes: 3

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