DWE

show databases; use mysql; show tables; select * from component; describe component; create database sql_intro; show databases; use sql_intro; create table emp_details (Name varchar(25), Age int, gender char(1), doj date, city varchar(15), salary float); describe emp_details; insert into emp_details  values("Jimmy",35,"M","2005-05-30","Chicago",70000), ("Shane",30,"M","1999-06-25","Seattle",55000), ("Marry",28,"F","2009-03-10","Boston",62000), ("Dwayne",37,"M", "2011-07-12","Austin", 57000), ("Sara",32,"F","2017-10-27","New York",72000), ("Ammy",35,"F","2014-12-20","Seattle",80000); select * from emp_details; select distinct city from emp_details; select count(name) as count_name from emp_details; select avg(salary) from emp_details; select name, age...

  BASIC OF REDUX: ##### Create a project with react. Then, 1) npm run start 2) npm install redux react-redux 3) create actions folder inside src folder. Create index.js file inside actions folder. 4) create reducers folder inside src folder and create upDown.js file inside reducers folder. 5) create store.js file inside src folder. 6) In app.js write: ``` import React from 'react' import "./App.css" const App = () => {   return (     <>       <div className="container">         <h1>Increment / Decrement counter</h1>         <h4>Using react and redux</h4>         <div className="quantity">           <a className="quantity__minus" title='Decrement'><span>-</span></a>           <input type="text" name='quantity' className='quantity__input'/>         ...

 Try the following code in terminal of project folder:  npx clear-npx-cache Then, run:  npx create-react-app projectname

 This error occurs as because may be you have used the following code:  const MongoStore= require('connect-mongo')(session); and app . use ( session ({     secret : ' keyboard cat ' ,     resave : false ,     saveUninitialized : false ,     store: new MongoStore({ mongooseConnection: mongoose.connection }) })); Now this is happening as because syntax have been changed (see the documentation here: documentation ) Solution that worked for me:  Use this:  const MongoStore = require ( ' connect-mongo ' ); and,  app . use ( session ({     secret : ' keyboard cat ' ,     resave : false ,     saveUninitialized : false , //false means don't create a session untitl it is stored     // store: new MongoStore({ mongooseConnection: mongoose.connection })     store : MongoStore . create ({         mongoUrl : process.env. MONGO_URI     }) }));

 Write: app . engine ( ' .hbs ' , exphbs. engine ({ defaultLayout : ' main ' , extname : ' .hbs ' })); Instead of  app . engine ( ' .hbs ' , exphbs({ defaultLayout : ' main ' , extname : ' .hbs ' }));