PHP code question?

Question

What does MYSQL mean in the following code.

require_once (MYSQL);

Answer 1

Looks to me like MYSQL is a constant. Look for something like this:

define('MYSQL', '/some/path/');

to get the 'real' include.

Answer 2

It's most likely a constant defined via define().

Answer 3

MYSQL would be a constant, defined by somewhere saying:

define("MYSQL", "/path/to/the/mysql/file.php");

Then, when they go to include/require it, it takes the defined path, and include/requires it.

Answer 4

It's (almost assuredly) referring to a constant that's define()d elsewhere.