猫鼬填充返回空数组 [英] Mongoose populate returning empty array

问题描述

我正在尝试使用 mongoose populate 函数，但作为回应，我得到了空数组，我已经看到多篇关于此的帖子

var MerchantSchema = new mongoose.Schema({包:[{ $type: mongoose.Schema.Types.ObjectId, ref: 'Package'}]},{typeKey: '$type',时间戳:{ createdAt:'created_at'，updatedAt:'updated_at'}});module.exports = mongoose.model('Merchant', MerchantSchema);

这是我对基本模型的架构定义.

var mongoose = require('mongoose');

var PackageSchema = new mongoose.Schema({商家 ID:{ 类型:mongoose.Schema.Types.ObjectId，参考:'商家'}，名称:字符串，original_price:数量，折扣价格:数量});module.exports = mongoose.model('Package', PackageSchema);

这就是我所指的模型.Package 模型和 Merchant 模型中的数据保存得很好.

商家文档

打包文档

但是如果我使用 populate 函数查询，我将返回一个空字符串

商家.findById( req.params.id, '包').populate('包').exec(函数(错误，商家){如果(错误)下一个(错误)；别的res.status(200).json(商家);});

输出:

<代码>{"_id": "579b3b2dc2e8d61c0ecd2731",包":[]}

谁能帮帮我

更新:

好吧，确实发生了一些奇怪的事情.如果我尝试使用 merchant_id 填充 Package 文档，它会正常工作，但反过来不行.

包.找().populate('merchant_id').exec(函数(错误，包){如果(错误)下一个(错误)；别的res.status(200).json(packages);});

输出:

<预><代码>[{"_id": "579b3b51c2e8d61c0ecd2732","name": "头发 + 指甲",原始价格":600，"discounted_price": 400,merchant_id":{"_id": "579b3b2dc2e8d61c0ecd2731","updated_at": "2016-07-29T11:17:37.474Z","created_at": "2016-07-29T11:17:01.216Z","name": "VLCC","logo_image": "http://vlccwellness.com/India/wp-content/uploads/2015/09/logo1.png?","cover_image": "http://image3.mouthshut.com/images/imagesp/925053993s.jpg?","__v": 1,标签":[]，包":[579b3b51c2e8d61c0ecd2732"],工作时间": {开场时间":1000，关闭时间":2100，"假日": "星期日"},信息": {"description": "Lorem Ipsum","性别": "男性",服务": [头发"],

解决方案

在 MerchantSchema 中使用 $type 的类型插入.

var MerchantSchema = new mongoose.Schema({包:[{ 类型:mongoose.Schema.Types.ObjectId，参考:'包'}]},{typeKey: '$type',时间戳:{ createdAt:'created_at'，updatedAt:'updated_at'}});module.exports = mongoose.model('Merchant', MerchantSchema);

根据您的商家文档中的包裹验证 ObjectId 数组.

I am trying to use mongoose populate function but in response I am getting empty array, I have seen multiple posts regarding this

var MerchantSchema = new mongoose.Schema({
  packages: [{ $type: mongoose.Schema.Types.ObjectId, ref: 'Package'}]
},
{
    typeKey: '$type',
    timestamps: { createdAt: 'created_at', updatedAt: 'updated_at'}
});

module.exports = mongoose.model('Merchant', MerchantSchema);

This is my schema definition for the base model.

var mongoose = require('mongoose');

var PackageSchema = new mongoose.Schema({
    merchant_id: { type: mongoose.Schema.Types.ObjectId, ref: 'Merchant' },
    name: String,
    original_price: Number,
    discounted_price: Number
});

module.exports = mongoose.model('Package', PackageSchema);

And this is the model I am referring to. The data inside the Package model and Merchant model is being saved just fine.

Merchant document

Package document

But if I query using populate function I am being returned an empty string

Merchant
.findById( req.params.id, 'packages')
.populate('packages')
.exec(function (err, merchant) {
    if (err)
        next(err);
    else
        res.status(200).json(merchant);
});

Output:

{
  "_id": "579b3b2dc2e8d61c0ecd2731",
  "packages": []
}

Can anyone help me

Update:

Ok something really odd is happening. If I try to populate the Package document with merchant_id it is working but not the other way around.

Package
    .find()
    .populate('merchant_id')
    .exec(function (err, packages) {
        if(err)
            next(err);
        else
            res.status(200).json(packages);
    });

Output:

[
  {
    "_id": "579b3b51c2e8d61c0ecd2732",
    "name": "Hair + Nails",
    "original_price": 600,
    "discounted_price": 400,
    "merchant_id": {
      "_id": "579b3b2dc2e8d61c0ecd2731",
      "updated_at": "2016-07-29T11:17:37.474Z",
      "created_at": "2016-07-29T11:17:01.216Z",
      "name": "VLCC",
      "logo_image": "http://vlccwellness.com/India/wp-content/uploads/2015/09/logo1.png?",
      "cover_image": "http://image3.mouthshut.com/images/imagesp/925053993s.jpg?",
      "__v": 1,
      "tags": [],
      "packages": [
        "579b3b51c2e8d61c0ecd2732"
      ],
      "work_hours": {
        "opening_time": 1000,
        "closing_time": 2100,
        "holiday": "Sunday"
      },
      "information": {
        "description": "Lorem Ipsum",
        "gender": "Men",
        "services": [
          "Hair"
        ],

解决方案

Use type insted of $type in MerchantSchema.

var MerchantSchema = new mongoose.Schema({
  packages: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Package'}]
},
{
    typeKey: '$type',
    timestamps: { createdAt: 'created_at', updatedAt: 'updated_at'}
});

module.exports = mongoose.model('Merchant', MerchantSchema);

Verify there is an array of ObjectId against packages in your Merchant document.

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