如何填充由Mongoose中的composite _id引用的字段？

Question

我有以下模式：

var WorkSchema = new Schema({ 
    _id:   Object, // {client: String, project: Number} 
    title:   String, 
    description: String 
}); 

var TimeWorkedSchema = new Schema({ 
    _id:   Object, // {client: String, date: Date} 
    work:   {type: Object, ref: 'Work'}, // {client: String, proyect: Number} 
    hours:   Number, 
    description: String 
}); 

var w = mongoose.model('Work', WorkSchema); 
var tw = mongoose.model('TimeWorked', TimeWorkedSchema); 

字段Work._id和TimeWorked.work是具有相同屬性的比較的對象。然後，我想填充TimeWorked模型與相應的工作數據和往常一樣：

tw.find().populate('work').exec(function(err, res){ 
    console.log(res); 
}); 

打印：

[{ 
"_id": { 
    "client": "clientX", 
    "date": "2017-04-20T00:00:00.000Z"}, 
"work": { 
    "_id":{      ┐ 
     "client": "clientX", | 
     "project": 1},   | invariable 
    "title": "ABC",    | 
    "description": "defgh"}, ┘ 
"hours": 4, 
"description": "bored" 
},{ 
"_id": { 
    "client": "clientY", 
    "date": "2017-04-15T00:00:00.000Z"}, 
"work": { 
    "_id":{      ┐ 
     "client": "clientX", | 
     "project": 1},   | invariable 
    "title": "ABC",    | 
    "description": "defgh"}, ┘ 
"hours": 8, 
"description": "funny" 
},{...etc...} 
] 

正如你可以看到，在所有返回的對象，在人口work場是相同的目的。

但是，如果我刪除填充方法（tw.find().exec(...)），我會得到原始work字段，它們實際上是不同的。

我認爲貓鼬還沒有實施這種類型的人口。我如何將兩個模式聯繫起來以在查詢中獲取組合數據？

Answer 1

從docs

注：物件，數字，字符串，和緩衝區有效用作參考文獻。

你需要這個$lookup。

tw.aggregate({ 
     $lookup: 
     { 
      from: "works", // collection name 
      localField: "work", 
      foreignField: "_id", 
      as: "work" 
     } 
    }).exec(function(err, res){ 
    console.log(res); 
});