Undefined function mysql_connect()

I have ran aptitude install php5-mysql (and restarted MySQL/Apache 2), but I am still getting this error:

Fatal error: Call to undefined function mysql_connect() in /home/validate.php on line 21

phpinfo() says the /etc/php5/apache2/conf.d/pdo_mysql.ini file has been parsed.

Answer

Well, this is your chance! It looks like PDO is ready; use that instead.

Try checking to see if the PHP MySQL extension module is being loaded:

<?php
    phpinfo();
?>

If it’s not there, add the following to the php.ini file:

extension=php_mysql.dll