The Node learning – 05 – mongo

Install the mongo

• Download: www.mongodb.com/download-ce…

• For details about how to install environment variables, see “Newbie”

• Validation:

mongod -version
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Enable and disable the MongoDB database

• Ensure that the data/ DB folder exists in the root directory of the disk where the installation directory resides.

• Enter mongod in CMD to start the database

• Example Modify a data store directory

  Mongod --dbpath= Data store directory pathCopy the code

• Stop: CTRL + C or close CMD directly

Basic Perception of MongoDB

Connecting to a Database

// Connect to the local MongoDB service mongo by defaultCopy the code

exit

exit
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Basic commands

• Show all databases

  show dbs
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• View the database for the current operation

  db
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• Creating a database

  Use database name (if not, it will be created)Copy the code

• Insert data

  db.students.insertOne({"name": "xxx"});
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• View all data

  db.students.find();
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Manipulate MongoDB data in Node

mongoose

Use third-party Mongoose to operate the MongoDB database

The installation

npm install --save mongodb
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Use the demo

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

const Cat = mongoose.model('Cat', { name: String });

// const kitty = new Cat({ name: 'Zildjian' });
// kitty.save().then(() => console.log('meow'));

for (var i = 0; i< 100; i++) {
    var kitty = new Cat({name: 'meow meow' + i});

    kitty.save().then(() = > {
        console.log('meow'); })}Copy the code

The basic concept

• Database, which can have multiple databases
• Data table -> collection, which is simply an array
• The document

{
    / / database
    qq: {
        / / collection
        users: [
            / / documentation
            {id: 1, name: 'aaa'}，
            {id: 2, name" 'bbb'} ], products: [] }, taobao: { }, baidu: { } }Copy the code

CRUD basic usage

/ / introduction
const mongoose = require('mongoose');
const Schema = mongoose.Schema;

// Connect to the database
// localhost ITcast database
// If the itcast database does not exist, it will be created automatically after the first database is inserted
mongoose.connect('mongodb://localhost/itcast');

// Design a collection structure/table structure
// Field names are the names of attributes in the table structure
const userSchema = new Schema({
    username: {
        type: String.required: true
    },
    password: {
        type: String.required: true
    },
    email: {
        type: String}});Publish the document structure as a model
// The mongoose. Model method is used to publish an architecture as a model
// The first argument: pass in an uppercase singular string to represent the database name, which Mongoose will automatically pass in
// The string of uppercase nouns generates the lowercase plural collective noun User -> users
// The second parameter, Schema
// Return value: model constructor
const User = mongoose.model('User', userSchema);

// Once you have the model construct data, you can use this constructor to add, delete, modify, and query the data in the user collection

// Add data
const admin = new User({
    username: 'admin'.password: '123456'.email: '[email protected]'
});
admin.save().then((res) = > {
    console.log(res);
    console.log('Saved successfully');
});

// Query data
// 1. Query all information
console.log('---------- query all -------------------');
User.find().then(res= > console.log(res));

// Query by condition, return an array
console.log('---------- by condition -------------------');
User.find({ username: 'ZS' }).then(res= > console.log(res));


// Only one object is returned
console.log('---------- query only one -------------------');
User.findOne({ username: 'ZS' }).then(res= > console.log(res));

// Delete data
User.deleteMany({ username: 'ZS' }).then(res= > console.log(res));

// Update data
User.findByIdAndUpdate("61061a42c988a30d10ec8e1d", { password: '123' })
    .then(res= > console.log(res));

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CRUD case rewritten by Mongoose

students.js

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/students', { useUnifiedTopology: true }, { useNewUrlParser: true });
const Schema = mongoose.Schema;

const studentSchema = new Schema({
    name: {
        type: String.required: true
    },
    gender: {
        type: String.enum: ['0'.'1'].required: true
    },
    age: {
        type: Number
    },
    hobbies: {
        type: String}});module.exports = mongoose.model('Student', studentSchema);
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router.js

const fs = require('fs');
const Student = require('./students.js');

const express = require('express');

1. Create a routing container
const router = express.Router();

// 2. Mount all routes to the route container

/ / the main interface
router.get('/students'.function (req, res) {
    Student.find(function (err, data) {
        if (err) {
            return res.status(500).send('Server error');
        }
        res.render('index.html', {
            students: data
        })
    })

})

// Add a page
router.get('/students/new'.function (req, res) {
    res.render('new.html');
})

// Click add
router.post('/students/new'.function (req, res) {
    const student =  new Student(req.body);
    student.save(function (err, data) {
        if (err) {
            return res.status(500).send('Server error');
        }
        res.redirect('/students');
    });

})

// Edit the page
router.get('/students/edit'.function (req, res) {
    Student.findById(req.query.id, function (err, data) {
        if (err) {
            return res.status(500).send('Server error');
        }
        res.render('edit.html', {
            student: data
        })
    })
})

// Click edit
router.post('/students/edit'.function (req, res) {
    const id = req.body.id;
    Student.findByIdAndUpdate(id, req.body, function (err, data) {
        if (err) {
            return res.status(500).send('Server error');
        }
        res.redirect('/students'); })})// Click delete
router.get('/students/delete'.function (req, res) {
    Student.findByIdAndRemove(req.query.id, function(err, data) {
        if (err) {
            return res.status(500).send('Server error');
        }
        res.redirect('/students');
    });
})

module.exports = router;

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