Nodejs connection with database applications
        create,read,update,delete 

        $ npm install mysql

     var mysql      = require('mysql');
     var connection = mysql.createConnection({
       host     : 'localhost',
       user     : 'me',
       password : 'secret',
       database : 'my_db'
     });

     connection.connect();

     connection.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
       if (error) throw error;
       console.log('The solution is: ', results[0].solution);
     });

     connection.end();

        var mysql = require('mysql');  
        var con = mysql.createConnection({  
        host: "localhost",  
        user: "root",  
        password: "***",  
        database: "nodejs"  
        });  
        con.connect(function(err) {  
        if (err) throw err;  
        console.log("Connected!");  
        var sql = "INSERT INTO employees (id, name, age, city) VALUES ?";  
        var values = [  
        ['2', 'Bharat Kumar', '25', 'Mumbai'],  
        ['3', 'John Cena', '35', 'Las Vegas'],  
        ['4', 'Ryan Cook', '15', 'CA']  
        ];  
        con.query(sql, [values], function (err, result) {  
        if (err) throw err;  
        console.log("Number of records inserted: " + result.affectedRows);  
        });  
        });       

        var mysql = require('mysql');  
        var con = mysql.createConnection({  
        host: "localhost",  
        user: "root",  
        password: "***",  
        database: "nodejs"  
        });  
        con.connect(function(err) {  
        if (err) throw err;  
        con.query("SELECT * FROM employees", function (err, result) {  
        if (err) throw err;  
        console.log(result);  
        });  
        });                     

        var mysql = require('mysql');  
        var con = mysql.createConnection({  
        host: "localhost",  
        user: "root",  
        password: "***",  
        database: "nodejs"  
        });  
        con.connect(function(err) {  
        if (err) throw err;  
        var sql = "UPDATE employees SET city = 'Delhi' WHERE city = 'Allahabad'";  
        con.query(sql, function (err, result) {  
        if (err) throw err;  
        console.log(result.affectedRows + " record(s) updated");  
        });  
        });

        var mysql = require('mysql');  
        var con = mysql.createConnection({  
        host: "localhost",  
        user: "root",  
        password: "***",  
        database: "nodejs"  
        });  
        con.connect(function(err) {  
        if (err) throw err;  
        var sql = "DELETE FROM employees WHERE city = 'Delhi'";  
        con.query(sql, function (err, result) {  
        if (err) throw err;  
        console.log("Number of records deleted: " + result.affectedRows);  
        });  
        });