In today's digital era, integrating various systems is a crucial part of web application development. Wordpress, being one of the most widely used website platforms, offers flexibility that allows connection to external databases. This article will guide you through the basic steps of connecting to an external database in WordPress.

Prerequisites

Before you begin, make sure you have the following:

• Access to your WordPress website with administrator rights.
• Access credentials to the external database, including hostname, username, password, and database name.
• Optionally, FTP access to your WordPress website if you need to modify files directly.

Step 1: Creating a Custom Plugin

The first step is to create a simple custom plugin that will enable the connection to the external database.

1. Log in to your WordPress admin panel and navigate to Plugins > Plugin Editor.
2. Create a new plugin by adding a new PHP file. You can name it, for example, my-external-db-connection.php.
3. Insert the following code into the file:

<?php
/**
 * Plugin Name: My External DB Connection
 * Description: Connection to an external database.
 * Version: 1.0
 * Author: Your Name
 */

function connect_to_external_database() {
    $external_db = new wpdb('username', 'password', 'database_name', 'hostname');
    if (!$external_db->error) {
        return $external_db;
    } else {
        wp_die('Connection to the external database failed: ' . $external_db->error);
    }
}

global $external_db;
$external_db = connect_to_external_database();
?>

Don't forget to replace 'username', 'password', 'database_name', and 'hostname' with your actual access credentials.

Step 2: Activating the Plugin

After creating the plugin, you need to activate it:

1. Go to Plugins > Installed Plugins in your WordPress admin interface.
2. Find the plugin "My External DB Connection" and click on "Activate".

Step 3: Using the External Database

Now that your plugin is active, you can perform queries to the external database using the global variable $external_db. For example:

global $external_db;
$results = $external_db->get_results("SELECT * FROM your_table");

You can place this code anywhere in your custom plugin or theme where you need to access the external database.

Security Considerations

When working with external databases, it's important to ensure security. Make sure that:

• Database access credentials are stored securely.
• You use secure methods for database querying to prevent SQL injection.
• The external database is secure and regularly updated.

Connecting WordPress to an external database can be a powerful tool for expanding your website's functionality. By following the steps outlined above and adopting best security practices, you can effectively integrate external data into your WordPress site.