mongoose關聯操做

時間 2019-12-02

原文原文鏈接

mongoose-ref

實現代碼github
最近在作一個項目涉及到mongoose的關聯查詢等等，以前作的mysql，postgresql比較多，而mongoose用的都是比較簡單的存儲數據，簡單查詢等等。
剛開始涉及ref仍是有點小暈的，查詢了相關資源，也能夠模模糊糊作出來，可是會有各類報錯。痛下決心研究透徹點，晚上熬夜到2點終於有點小眉目了。node

node v8.5.0
mongodb
結合一個接口理解
結合promise-async-await

通常採用mvc模式，本文就直接在express裏直接寫了

1. 首先創建了一個mongoose-ref項目

直接使用了express -e mongoose-ref

2.在routes/index裏鏈接mongodb數據庫

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/ref');複製代碼

3.創建4個模型，用戶：User,城市：City,省份：State,國家：Country

同時創建關聯user->city->state->country

const Schema = mongoose.Schema;
const ObjectId = Schema.Types.ObjectId;
const UserSchema = new Schema({
  username: { type: String },
  userpwd: { type: String },
  userage: { type: Number },
  city: { type: Schema.Types.ObjectId, ref: 'City' },
});
const CitySchema = new Schema({
  name: { type: String },
  state: { type: Schema.Types.ObjectId, ref: 'State' }
});
const StateSchema = new Schema({
  name: { type: String },
  country: { type: Schema.Types.ObjectId, ref: 'Country' }
});
const CountrySchema = new Schema({
  name: { type: String }
});
const User = mongoose.model('User', UserSchema);
const City = mongoose.model('City', CitySchema);
const State = mongoose.model('State', StateSchema);
const Country = mongoose.model('Country', CountrySchema);複製代碼

4.主要採用promise-async-async進行邏輯處理

首先建立一個user_getCountryList函數，以下代碼

const user_getCountryList = async function (req, res) {
  console.log("/v1/ref start -->" + JSON.stringify(req.body));
  try {
    const respondData = {
      status: res.statusCode,
      data: {},
      error: {}
    };
    const username = req.body.username;
    const userpwd = req.body.userpwd;
    const userage = req.body.userage;
    const usercityname = req.body.usercityname;
    const userstatename = req.body.userstatename;
    const usercountryname = req.body.usercountryname;
    const userInfoCountry = await findUserCountry({ name: usercountryname }, usercountryname);//查看國家
    const userInfoState = await findUserState({ name: userstatename }, userstatename);//查看州
    const userInfoCity = await findUserCity({ name: usercityname }, usercityname);//查看城市
    const userInfo = await findUser({ username: username, }, username,userpwd,userage);//查看用戶信息
    const updateInfoUser = await updateUser({ _id: userInfo },userInfoCity);//更新用戶信息
    const updateInfoCity = await updateCity({ _id: userInfoCity }, userInfoState);//更新城市信息
    const updateInfoState = await updateState({ _id: userInfoState }, userInfoCountry);//更新州信息
    return res.json(respondData);
  }
  catch (error) {
    //錯誤處理
    console.log("userCity error -->" + JSON.stringify(error));
    respondData.error = error;
    return res.json(respondData);
  }
}複製代碼

首先查看傳入的國家在country中有沒有，加入有，返回_id,沒有就建立傳入的國家名，並返回_id,查看findUserCountry函數對應的邏輯

const findUserCountry = async function (cnd, country) {
  console.log("findUserCountry start --> " + JSON.stringify(cnd));
  return new Promise(function (resolve, reject) {
    Country.findOne(cnd, function (error, data) {
      console.log("findUserCountry findOne data --> " + JSON.stringify(data));
      if (error) {
        return reject(error);
      }
      if (data) {
        return resolve(data._id);
      } else {
        const userCountry = new Country({
          name: country
        });
        userCountry.save(function (err, data) {
          if (err) {
            console.log("userCountry.save err-->" + JSON.stringify(err));
            return reject(err);
          }
          console.log("userCountry-->" + JSON.stringify(data));
          return resolve(data._id);
        });
      }
    });
  })
}複製代碼

同理傳入的州，城市，用戶信息以一樣的方式返回_id

接下來就要進行關聯user->city->state->country

通俗的說就是在User表中city保存City表中所須要的_id;也就是以前返回的_id這時就能夠用到，能夠參考updateUser函數

const updateUser = async function (cnd, cityid) {
  console.log("updateUser start --> " + JSON.stringify(cnd));
  return new Promise(function (resolve, reject) {
    User.update(cnd, { $set: { city: cityid } }, function (error, data) {
      console.log("updateUser findOne data --> " + JSON.stringify(data));
      if (error) {
        return reject(error);
      }
      return resolve(data);
    });
  })
}複製代碼

可使用postman模擬數據，如圖：

這時就把City對應的_id寫進了User表中，能夠查看錶，如圖：

同理user->city->state->country數據均可以寫進不一樣的表中。

5.使用populate關聯查詢

當傳入username 時,使用populate關聯查詢,能夠查詢出這我的的因此信息mysql

User.find({ username: user_name })
    .populate('city')
    .exec(function (err, docs) {
      City.find({ _id: docs[0].city._id })
        .populate('state')
        .exec(function (err, doc) {
          State.find({ _id: doc[0].state._id })
            .populate('country')
            .exec(function (err, result) {
              const userInfo = {};
              userInfo.username = docs[0].username;
              userInfo.userpwd = docs[0].userpwd;
              userInfo.userage = docs[0].userage;
              userInfo.usercity = doc[0].name;
              userInfo.userstate = result[0].name;
              userInfo.usercountry = result[0].country.name;
              respondData.data.push(userInfo);
              return res.json(respondData);
            })
        })
    });複製代碼