node.js - Mongoose Population ObjectId 引用正在消失？

Question

我简化了以下代码:

var buySchema = new mongoose.Schema({
    userid:String,
    timestamp:Number,
    price:Number
});
var cardSchema = new mongoose.Schema({
    cardid: String,
    buy:[{type:mongoose.Schema.Types.ObjectId, ref:'buy'}],
});

var Card = mongoose.model('cards',cardSchema,'cards');
var Buy = mongoose.model('buy',buySchema,'buy');

Card.findOne({'cardid':cardid}, function(err, card) {

    var newBuy = new Buy({'userid':userid, timestamp:null,price:null});

    newBuy.save(function(err){
      card.buy.addToSet(newBuy._id);
    });

    card.save(function(err,card){
      console.log(card.buy); // card.buy[] has an ObjectId ref
    });

});

Card.findOne({'cardid':cardid}, function(err, card) {
   console.log(card.buy); // !!!!! card.buy[] does not have ObjectId ref !!!!!
});

buy[] 似乎也没有在 mongodb 中保存 ObjectId 引用

如果没有 ObjectId 引用，我以后该如何填充卡片？他们去哪儿了？关于人口我没有得到什么？

Answer 1

您必须为 ref:'buy' 添加引号并添加正确的架构。看mongoose js docs .

var cardSchema = new mongoose.Schema({
    cardid: String,
    buy:[{type:mongoose.Schema.Types.ObjectId, ref:'buy'}],
});

var Card = mongoose.model('cards',cardSchema);
var Buy = mongoose.model('buy',buySchema);