Node.js Connection to MySQL, MariaDB and Percona

Connect a Node.js application hosted on the platform to MySQL, MariaDB, or Percona by installing a compatible Node.js database driver and using the database hostname, username, password, and database name supplied for the database node.

Create the Environment

Prepare the Database

Install the Node.js MySQL Driver

Connect to the Node.js application-server node and install the MySQL package:

npm install mysql

The package provides the connection, query, and connection-closing methods used by the example below.

Create the Database Connection

Create a JavaScript file, for example connection.js, and add the database connection settings:

var mysql = require('mysql');

var connection = mysql.createConnection({
    host: '{host}',
    user: '{user}',
    password: '{password}',
    database: '{database}'
});

connection.connect(function(err) {
    if (err) {
        console.error('Database connection failed: ' + err.stack);
        return;
    }

    console.log('Connected to the database.');
});

Execute a Test Query

Use the query() method to verify database access:

connection.query(
    'SELECT 1 + 1 AS solution',
    function(err, rows) {
        if (err) {
            throw err;
        }

        console.log('Result: ', rows[0].solution);
    }
);

connection.end(function(err) {
    if (err) {
        return console.log(
            'Error while closing connection: ' + err.message
        );
    }

    console.log('Database connection closed.');
});

Run the script from the Node.js server:

node connection.js

A successful connection and query should return a result of 2.

Connection Pooling

For applications handling many concurrent requests, use a connection pool instead of creating a new database connection for every request.

var mysql = require('mysql');

var pool = mysql.createPool({
    connectionLimit: 10,
    host: '{host}',
    user: '{user}',
    password: '{password}',
    database: '{database}'
});

pool.query(
    'SELECT 1 + 1 AS solution',
    function(err, rows) {
        if (err) {
            throw err;
        }

        console.log(rows[0].solution);
    }
);

Expected Result

The Node.js application establishes a database connection using the configured hostname and credentials, executes a test SQL query successfully, returns the result, and closes or releases the connection correctly.

Important Notes

• Do not use localhost when the database is running in another container.
• Install a compatible MySQL driver in the Node.js application.
• Use the database hostname without http:// or https://.
• Use a dedicated database user with only the required privileges.
• Use connection pooling for applications with concurrent database requests.
• Store credentials in environment variables for production deployments.

Common Issues and Solutions