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Aggregate cascade query implementation steps

May 10, 2018 pm 02:15 PM
Inquire step

This time I will bring you the steps to implement aggregate cascade query. What are the precautions for implementing aggregate cascade query? The following is a practical case, let's take a look.

I recently completed a nodejs mongoose project and encountered the cascade query operation of

mongodb. The situation is to implement a ranking list to view the top ten people who have published the most valid articles among the customers of a certain company (organization).

Account table: Company information exists in a separate account table.

var AccountSchema = new Schema({
  loginname: {type: String},
  password: {type: String},
  /**
   * 联系方式
   */
  //账户公司名
  comName: {type: String},
  //地址
  address: {type: String},
  //公司介绍
  intro: {type: String}
});
mongoose.model('Account', AccountSchema);
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Cusomer table: The company’s customer base.

var CustomerSchema = new Schema({
  /**
   * 基本信息
   */
  //密码
  password: {type: String},
  //归属于哪个Account
  belongToAccount: {type: ObjectId, ref: 'Account'},
  //手机号,登录用
  mobile: {type: String},
  //真实姓名
  realname: {type: String}
});
CustomerSchema.index({belongToAccount: 1, mobile: 1}, {unique: true});
mongoose.model('Customer', CustomerSchema);
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article table

var articleSchema= new Schema({
  belongToAccount: {type: ObjectId, ref: 'Account'},
  title: {type: String},
  text: {type: String},
  createTime: {type: Date, default: Date.now},
  author: {type: ObjectId, ref: 'Customer'},
  //0,待确认,1 有效 ,-1 无效
  status: {type: Number, default: 0}
});
articleSchema.index({belongToAccount: 1, createTime:-1,author: 1}, {unique: false});
mongoose.model('article', articleSchema);
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What we need to do here is to organize and sort the soft articles by accountId→aggregate→cascade author to find the author's name and other information.

The code is as follows:

exports.getRankList = function (accountid, callback) {
  AticleModel.aggregate(
    {$match: {belongToAccount: mongoose.Types.ObjectId(accountid), status: 1}},
    {$group: {_id: {customerId: "$author"}, number: {$sum: 1}}},
    {$sort: {number: -1}}).limit(10).exec(function (err, aggregateResult) {
    if(err){
      callback(err);
      return;
    }
      var ep = new EventProxy();
      ep.after('got_customer', aggregateResult.length, function (customerList) {
        callback(null, customerList);
      });
       aggregateResult.forEach(function (item) {
        Customer.findOne({_id: item._id.customerId}, ep.done(function (customer) {
          item.customerName = customer.realname;
          item.customerMobile=cusomer.mobile;
          // do someting
          ep.emit('got_customer', item);
        }));
      })
    });
};
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The returned result format (there are only two records here, actually the top ten):

[ { _id: { customerId: 559a5b6f51a446602032fs21 }, number: 5,
customerName: 'test2',
mobile:22 } ,
{ _id: { customerId: 559a5b6f51a446602041ee6f }, number: 1,
customerName: 'test1',
mobile: 11 } ]
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I believe you have mastered it after reading the case in this article Method, for more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

Detailed explanation of the steps to add events to dynamically created elements using JS

vue uploads images to the database on the front-end page exhibit

The above is the detailed content of Aggregate cascade query implementation steps. For more information, please follow other related articles on the PHP Chinese website!

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