mongoose-ref

实现代码github 最近在做一个项目涉及到mongoose的关联查询等等,之前做的mysql,postgresql比较多,而mongoose用的都是比较简单的存储数据,简单查询等等。刚开始涉及ref还是有点小晕的,查询了相关资源,也可以模模糊糊做出来,但是会有各种报错。痛下决心研究透彻点,晚上熬夜到2点终于有点小眉目了。

node v8.5.0

mongodb

结合一个接口理解

结合promise-async-await

一般采用mvc模式,本文就直接在express里直接写了

1. 首先建立了一个mongoose-ref项目

直接使用了express -e mongoose-ref

2.在routes/index里连接mongodb数据库

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

3.建立4个模型,用户:User,城市:City,省份:State,国家:Country

同时建立关联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);

4.主要采用promise-async-async进行逻辑处理

首先创建一个user_getCountryList函数,如下代码

 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);//查看国家
 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);//查看用户信息
 const updateInfoUser = await updateUser({ _id: userInfo },userInfoCity);//更新用户信息
 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) {
 //错误处理
 console.log("userCity error -->" + JSON.stringify(error));
 respondData.error = error;
 return res.json(respondData);
 }
 }

首先查看传入的国家在country中有没有,加入有,返回_id,没有就创建传入的国家名,并返回_id,查看findUserCountry函数对应的逻辑

 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);
 });
 }
 });
 })
 }

同理传入的州,城市,用户信息以同样的方式返回_id

接下来就要进行关联user->city->state->country

通俗的说就是在User表中city保存City表中所需要的_id;也就是之前返回的_id这时就可以用到,可以参考updateUser函数

 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);
 });
 })
 }

可以使用postman模拟数据,如图: Postman模拟接口请求这时就把City对应的_id写进了User表中,可以查看表,如图: User表中数据 City表中数据同理user->city->state->country数据都可以写进不同的表中。

5.使用populate关联查询

当传入username 时,使用populate关联查询,可以查询出这个人的所以信息

 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);
 })
 })
 });

使用postman模拟接口如下 Postman模拟接口关联查询