wp config database conditional

wp-config.php

<?php
// ... An alternative to a multisite config while using the same codebase.
// ... In my use case: parent and child theme with two different domains. Multisite not wanted. (although it would make life easier)
// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
$domain_one = preg_match( '/domainone\.com/', $_SERVER['SERVER_NAME'] );
$domain_two = preg_match('/domaintwo\.com/', $_SERVER['SERVER_NAME'] );

if ( $domain_one ) {
	define('DB_NAME', 'database_one');
} else if ( $domain_two ) {
	define('DB_NAME', 'database_two');
}

//...