Javascript 如何查询集合值​；和参考文件值​；在MongoDB？

我不知道我如何正确地表述这个问题。我需要对这两个值执行查询​​集合和值的​​引用对象的名称

原始集合如下所示：

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dadf",
      "name": "Michael",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504b",
          "kind": "advertiser",
          "group": "instagram"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dade",
      "name": "Frank",
      "district": "Washington",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504a",
          "kind": "developer",
          "group": "school"
        }
      ]
    }
  ]
}

当执行满足条件的查询时，我需要得到以下结果：

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dadf",
      "name": "Michael",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504b",
          "kind": "advertiser",
          "group": "instagram"
        }
      ]
    }
  ]
}

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dade",
      "name": "Frank",
      "district": "Washington",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504a",
          "kind": "developer",
          "group": "school"
        }
      ]
    }
  ]
}

在此条件下：

kind==“developer”

，得到以下结果：

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dadf",
      "name": "Michael",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504b",
          "kind": "advertiser",
          "group": "instagram"
        }
      ]
    }
  ]
}

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    },
    {
      "_id": "5fe72f0b4fd2c131bcc7dade",
      "name": "Frank",
      "district": "Washington",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504a",
          "kind": "developer",
          "group": "school"
        }
      ]
    }
  ]
}

对于满足以下条件的查询：

district==“Texas”&&kind==“developer”

，获取结果：

{
  "houses": [
    {
      "_id": "5fe72f0b4fd2c131bcc7dae0",
      "name": "John",
      "district": "Texas",
      "events": [
        {
          "_id": "5fe73e91ede45b3d2eca504c",
          "kind": "developer",
          "group": "facebook"
        }
      ]
    }
  ]
}

查询应使用express路线内的mongoose执行，并且应是通用的，处理不同的请求参数集：

router.get('/report', (req, res) => {
  let params = {}; 
  let { district, kind } = req.headers;

  if (district) params["district"] = district;
  if (kind) params["kind"] = kind;
  // Here should be the query
});

房屋

模型参考

事件

：

const mongoose = require('mongoose');

const Schema = mongoose.Schema;

const HouseSchema = new Schema({
  name: String,
  district: String,
  events: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Event'
  }]
});

module.exports = mongoose.model('House', HouseSchema);

---

我正在学习MongoDB和aggregation，但我对它的所有功能都不太了解。请告诉我如何以传统方式正确执行此类请求？我将非常感激

DBRef是一个客户端构造。在服务器端使用它并不容易。

db.collection.aggregate([
{$unwind:"$houses"},
{$match:{"houses.district":"Texas","houses.events":{$elemMatch:{"kind":"developer"}}}},
{$group:{
    _id:null,
    houses:{$push:"$houses"}
}},
{$project:{_id:0}}])