Udfyld en mangustmodel med et felt, der ikke er et id

Dette er understøttet siden Mongoose 4.5 , og kaldes virtuel population .

Du skal definere dine fremmednøgleforhold efter dine skemadefinitioner og før du opretter modeller , sådan her:

// Schema definitions

BookSchema = new mongoose.Schema({
        ...,
        title: String,
        authorId: Number,
        ...
    },
    // schema options: Don't forget this option
    // if you declare foreign keys for this schema afterwards.
    {
        toObject: {virtuals:true},
        // use if your results might be retrieved as JSON
        // see http://stackoverflow.com/q/13133911/488666
        //toJSON: {virtuals:true} 
    });

PersonSchema = new mongoose.Schema({id: Number, ...});


// Foreign keys definitions

BookSchema.virtual('author', {
  ref: 'Person',
  localField: 'authorId',
  foreignField: 'id',
  justOne: true // for many-to-1 relationships
});


// Models creation

var Book = mongoose.model('Book', BookSchema);
var Person = mongoose.model('Person', PersonSchema);


// Querying

Book.find({...})
    // if you use select() be sure to include the foreign key field !
    .select({.... authorId ....}) 
    // use the 'virtual population' name
    .populate('author')
    .exec(function(err, books) {...})