4th floor React-Js class those who don't have aof drive

COME TO CLASS REACT-JS CLASS

MERN STACK
M= MONGODB is database
E= EXPRESS-JS is framework
R= REACT-JS is frontend
N= NODE-JS is backend


node-js depending on express-js
express-js used to develop rest api
express-js used to do (get, post , put, delete)requests

STEP1- react-js sends request to node-js
STEP2- node-js sends request ri mongodb
STEP3- mongodb sends back request to nodejs
STEP4- node-js sends back request to react-js

mongodb:-

it is NoSQL database
it supports JSON
it is light-weight database
it follows the mongoDB protocol
it bydefault running on Port no.27017

Difference b/w SQL & NoSQL databases ?
SQL NoSQL
1. oracle , MYsql 1. mongoDB , casandraDB
sqlServer


2. tables , primaryKey 2. collections , _id
3. databases , records 3. databases , documents

DataBase Name : mnl_database

Collection Name : products

user name : admin

password : admin

URL : mongodb+srv://admin:admin@mnlbatch.3fgzquk.mongodb.net/?retryWrites=true&w=majority

NODE-JS

1. it is backend technology
2. used to develop server side apps
3. we develop node-js apps with the help of javascript
4. it supports libraries or modules
5. we will download libraries/modules with the help of either npm or yarn


libraries:-

1. Express-JS:-express library used to develop restAPIs.
2. mongoDB:- this library used to connect to mongoDB database
3. cors:- this library used to enable cors policy

NODE-JS

Step1:- create the folder for backend

Step2:- download libraries (yarn add express mongodb cors)
if not npm init

Step3:- create server.js file

//import modules
//require is the function used to import modules
const express = require("express");
const mongodb = require("ongodb");
const cors = require("cors");
//create rest object to do Get post put delete
//rest obj used to develop restAPIs
const app =express();
//where app is the rest object
//while working with network we use to prefer JSON
app.use(express.json());
//enable cors policy
app.use(cors());
// to interact with MongoDB database we have to create client object
//by using client object only we can interact with MongoDB database
const client = mongodb.MongoClient;
// create get request
app.get(`/products`, (req,res)=>{
client.connect(`url`,(err,connection)=>{
if(err) throw err;
else{
const db = connection.db("AmanRash");
db.connection("products").find().toArray((err,array)=>{
if(err) throw err;
else{res.json(array);
}
})
}
});
});

http://localhost:8080/products

app.post("/Insert, (req, res)



client.connect mongodbery://adi:adingbatch, fgquksongodb.net/?

retrylerites-trunjority,(err,connection)


if(err) throw err;



else


const db connection.db"database");



db.collection("products")("id", body a body.o_name," cost" req. body a cost)

if(err) throw err:



else

res.json((message: "record Inserted successfully":

Line 66 :- update mnl_database

Conducting for 3hour only will explain how to program and one question of last session (what's the real-time implementation of abstract classes ). 10am -1 pm

Timing 10-11am only

Fill this form to get meeting link n access

Old members check your calendar updated there

Next Sunday again we will be covering core java, advance java, Spring and spring boot , React-Js

Will try to cover everything but be available as we will cover things fast in-depth

public static void main(String[] args) {
double a ,b ;
a= System.currentTimeMillis();
List<Double> list = of(1, 1000000000).boxed().collect(Collectors.toList());
list.forEach(obj -> System.out.print(obj));
b=System.currentTimeMillis();
System.out.println(b-a);
}
}