Warning: Use of undefined constant DB_USERNAME - assumed 'DB_USERNAME' (this will throw an Error in a future version of PHP) in /home/elvin39/public_html/system/config/catalog.php on line 13

Warning: Use of undefined constant DB_PASSWORD - assumed 'DB_PASSWORD' (this will throw an Error in a future version of PHP) in /home/elvin39/public_html/system/config/catalog.php on line 14

Warning: Use of undefined constant DB_DATABASE - assumed 'DB_DATABASE' (this will throw an Error in a future version of PHP) in /home/elvin39/public_html/system/config/catalog.php on line 15

Fatal error: Uncaught Exception: Error: Could not make a database link using DB_USERNAME@localhost! in /home/elvin39/public_html/system/library/db/mysqli.php:31 Stack trace: #0 /home/elvin39/storage/modification/system/library/db.php(80): DB\MySQLi->__construct('localhost', 'DB_USERNAME', 'DB_PASSWORD', 'DB_DATABASE', '3306') #1 /home/elvin39/public_html/system/framework.php(80): DB->__construct('mysqli', 'localhost', 'DB_USERNAME', 'DB_PASSWORD', 'DB_DATABASE', '3306') #2 /home/elvin39/public_html/system/startup.php(105): require_once('/home/elvin39/p...') #3 /home/elvin39/public_html/index.php(20): start('catalog') #4 {main} thrown in /home/elvin39/public_html/system/library/db/mysqli.php on line 31