How to provide a mysql database connection in single file in nodejs

Question

I need to provide the mysql connection for modules. I have a code like this.

var express = require(\'express\'),
app = express(),
server = require(\'http\').         


        

Answer 1

From the node.js documentation, "To have a module execute code multiple times, export a function, and call that function", you could use node.js module.export and have a single file to manage the db connections.You can find more at Node.js documentation. Let's say db.js file be like:

    const mysql = require('mysql');

    var connection;

    module.exports = {

    dbConnection: function () {

        connection = mysql.createConnection({
            host: "127.0.0.1",
            user: "Your_user",
            password: "Your_password",
            database: 'Your_bd'
        });
        connection.connect();
        return connection;
    }

    };

Then, the file where you are going to use the connection could be like useDb.js:

const dbConnection = require('./db');

var connection;

function callDb() {

    try {

        connection = dbConnectionManager.dbConnection();

        connection.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
            if (!error) {

                let response = "The solution is: " + results[0].solution;
                console.log(response);

            } else {
                console.log(error);
            }
        });
        connection.end();


    } catch (err) {
        console.log(err);
    }
}