貓鼬子文檔訪問

Question

如何訪問已找到的文檔上的子文檔？

比方說，我創建了以下型號：

const mongoose = require('mongoose'); 
const schema = mongoose.Schema; 

const barStructure = { 
    name: { type: String, require: true } 
} 

const fooStructure = { 
    name: { type: String, require: true }, 
    bar: { type: schema.ObjectId, ref: 'bar', require: false } 
} 

var BarModel = mongoose.model('Bar', schema(barStructure)); 
var FooModel = mongoose.model('Foo', schema(fooStructure)); 

，然後創建：

FooModel.create({ name: 'name', bar: new BarModel({ name: 'name' }) }); 

現在，我怎麼訪問bar從父？

FooModel.findOne({ name: 'name' }, (err, result) => { 
    //How can I access bar here? 
}); 

Answer 1

可以使用貓鼬Query Population功能：

fooModel 
    .findOne({ name: 'name' }) 
    .populate('bar') 
    .exec((err, foo) => { 
    if (err) return handleError(err); 
    console.log(foo.bar): // Access sub model 
    });