Node.js driver MongoDB basic use tutorial

Using mongoose allows us to better use the mongodb database without having to write tedious business logic.

The installation

npm install mongoose

Initial use
Before using mongoose, you need to install node and mongodb. The installation method of node and mongodb is not discussed here.

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

Quick start
In mongoose, all data is a schema, and each schema maps to an mongodb collection and defines the collection file structure.

 // Set up here 1 All animals have all the attributes of this mode 
 var animalSchema = new Schema({
  name: String,
  age: Number,
 });

Models are a variety of constructors that we define from Schema. Instans of models can use many operations. All document creation and retrieval is handled by the model

 var animalMode = db.model('Animal', animalSchema);

Instance models are essentially files that can be easily created and modified

 var cat = new animalMode({
  name: 'catName',
  age: '7', // I'm still using strings here, mongoose The type is automatically converted 
  });

 cat.save(function(err, thor) {
  if (err) return console.log(err);
  console.log(thor);
 });
 // Or you can use create
 //cat.create(function(err, thor) {
 // if (err) return console.log(err);
 // console.log(thor);
 //});

 // Perform a lookup 
 animalMode.find(function(err, people){
  if(err) console.log(err);
  console.log(people);
 });
 // Find the qualifying data 
 animalMode.findOne({title: 'catName'}, function(err, cat){
  if(err) console.log(err);
  console.log(cat);
 });

Schema
The data type

This is all data types in Schema, including mongoose custom data types

String Number Date Buffer Boolean Mixed ObjectId Array

Use of each data type

 var animalMode = mongoose.model('Animal', schema);

 var cat = new animalMode;
 cat.name = 'Statue of Liberty'    //String
 cat.age = '7';        //Number
 cat.updated = new Date;      //Date
 cat.binary = new Buffer(0);     //Buffer
 cat.living = false;       //Boolean
 cat.mixed = { any: { thing: 'i want' } }; //Mixed    
 cat._someId = new mongoose.Types.ObjectId; //ObjectId
 cat.ofString.push("strings!");    //Array

Because Mixed does not define specific content, it can be used with {}. The following two definitions are equivalent.

 var animalSchema = new Schema({any: {}});
 var animalSchema = new Schema({any: {Schema.Types.Mixed}});

Custom method

You can bind methods to Schema

 var animalSchema = new Schema({
  name: String,
  age: Number,
 });

 animalSchema.methods.findSimilarTypes = function (cb) {
  return this.model('Animal').find({ name: this.name }, cb);
 }

 var animalMode = db.model('Animal', animalSchema);

 cat.findSimilarTypes(function(err, cat){
  if(err) console.log(err);
  console.log(cat);
 });

It is also possible to add static methods to Schema

 animalSchema.statics.findByName = function (name, cb) {
  return this.find({ name: new RegExp(name, 'i') }, cb);
 }
 var animalMode = db.model('Animal', animalSchema);

 animalMode.findByName('catName', function (err, animals) {
  console.log(animals);
 });

The index

We can index mongodb data. mongodb supports two levels of indexing. In order to improve data lookup and location, it is necessary to build composite indexes

 var animalSchema = new Schema({
  name: String,
  age: Number,
  tags: { age: [String], index: true } // field level
 });

 animalSchema.index({ name: 1, age: -1 }); // schema level

However, this type of indexing can cause significant performance impacts. It is recommended to stop in production and set automatic indexing in setup mode to false disable

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

0

Model
C

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

1

R

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

2

U
The official documentation provides the update function Model.update

Model.update(conditions, doc, [options], [callback])

conditions update condition doc Update option update option safe (boolean) security mode, default option, value is true upsert (boolean) whether to create a new document if the condition does not match. The default value is false multi (boolean) Whether to update multiple files, the default value is false strict (boolean) is in strict mode with only one data update overwrite (boolean) overrides data, default to false callback err returns a value when data is updated in error numberAffected (I don't know) Number of rows affected in rawResponse

animalMode.update({name: 'catName'}, {age: '6'}, {multi : true}, function(err, numberAffected, raw){
 if (err) return console.log(err);
 console.log('The number of updated documents was %d', numberAffected);
 console.log('The raw response from Mongo was ', raw);
});

D

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

4

other
// Returns the number of documents

 var mongoose = require("mongoose");
 var Schema = mongoose.Schema;
 var db = mongoose.connection;
 mongoose.connect('mongodb://localhost/animal');
 db.on('error', console.error);
 db.once('open', function() {
  // Patterns and models are built here 
 }

5