Nodejs operation mongodb two (mongoose operation mongodb)

One, nodejsuse inmongodb

• 1. mongoosejsDocument

• 2. Installation package

  npm i mongoose --save
  

Second, mongoosethe basic steps used

• 1. Installation package

• 2. Connect to the database

  const mongoose = require('mongoose');
  // 连接到数据库
  mongoose.connect('mongodb://localhost/nest_cms');
  // 如果有用户名与密码的连接方式
  // mongoose.connect('mongodb://用户名:密码@地址:端口号/数据库');
  // mongoose.connect('mongodb://root:123456@localhost/nest_cms');
  

• 3. Definitionschema

  // 使用命令查看数据库中的表 show collections 或者定义新的
  const OrderSchema = mongoose.Schema({
        
        
    order_id: String,
    uid: Number,
    trade_no: String,
    all_price: Number,
    all_num: Number,
  })
  

• 4. Create a data model

  mongoose.modelYou can pass in two parameters or three parameters. However, it is recommended to use three parameters, when the collection name may be inconsistent with the model name

  • The mongoose.model(参数 1:模型名称(首字母大写)，参数 2:Schema)third parameter of the two parameters will be Morgan based on the lowercase letter of the first parameter
  • Three parametersmongoose.model(参数 1:模型名称(首字母大写)，参数 2:Schema, 参数 3:数据库集合名称)

  const Order = mongoose.model('Order', OrderSchema, 'order');
  

• 5. Perform a series of operations

  // 实例化数据模型,创建数据的时候需要save
  const order1 = new Order({
        
        
    order_id: '2',
    uid: 5,
    trade_no: '333',
    all_price: 20,
    all_num: 4,
  })
  order1.save()
  
  // 查询数据
  Order.find({
        
        }, (err, docs) => {
        
        
    if (err) {
        
        
      console.log('查询错误');
    }
    console.log(JSON.stringify(docs));
  })
  

3. Basic operations of adding, deleting, modifying and checking

• 1. Increase data

  The added data must use the instantiated object and then call the save()function

  const order1 = new Order({
        
        
    order_id: '2',
    uid: 5,
    trade_no: '333',
    all_price: 20,
    all_num: 4,
  })
  order1.save()
  

• 2. Delete data

  // 删除数据
  Order.deleteOne({
        
        _id: '5e0fd41ca53860217c5831bd'}, (err) => {
        
        
      if (err) {
        
        
          console.log('删除失败');
      }
      console.log('删除成功');
  })
  

• 3. Modify the data

  // 修改数据
  Order.updateOne({
        
        _id: '5e0fd4bb08ad70786fd8ac84', all_num: 2}, {
        
        all_num: 5}, (err, res) => {
        
        
      if (err) {
        
        
          console.log('修改数据错误')
      }
      // { n: 1, nModified: 1, ok: 1 }
      console.log(res);
  });
  

• 4. Query data

  Order.find({
        
        }, (err, docs) => {
        
        
      if (err) {
        
        
          console.log('查询错误', err)
      }
      console.log(JSON.stringify(docs));
  })
  

Fourth, mongoosemodularization and packaging of individual links

• 1. Another mongooseconnection method

  // 第一步
  const mongoose = require('mongoose');
  
  // 第二步连接数据库
  mongoose.connect('mongodb://root:123456@localhost/nest_cms', {
        
         useNewUrlParser: true }, (err) => {
        
        
      if (err) {
        
        
          console.log('连接错误');
          return;
      }
      console.log('mongodb连接成功');
  });
  

• 2. Separately encapsulate the connection into a module (other places are quoted in simple mode, and only connect once)

  // 第一步
  const mongoose = require('mongoose');
  
  // 第二步连接数据库
  mongoose.connect('mongodb://root:123456@localhost/nest_cms', {
        
         useNewUrlParser: true }, (err) => {
        
        
      if (err) {
        
        
          console.log('连接错误');
          return
      }
      console.log('mongodb连接成功');
  });
  
  module.exports = mongoose;