PHP oddities

Posted under » PHP on 29 April 2009

There are some things which I find irksome in PHP. I will list them here as I come across it.

Notice: Undefined index:

if (isset($_GET['taxo'])) 
{$taxo = $_GET['taxo'];}

Applies to $_GET and $_POST stuff.

Notice: Use of undefined constant

$greg=$solatime['greg'];

Without the bracket (quotes) will give an error. Notice: Use of undefined constant greg - assumed 'greg'. Not a critical error and you if you turn off all notices, you will not see the error messages.

Date and NULL issue

Not specifically a PHP issue but a MySQL one as well. You cannot insert or update "" into date format. You should use "0000-00-00" instead. You cannot use NULL most of the time because sometimes you already put "$thedatefield" hence will be translated into "NULL".

the backslash in form issue

Be carefull when your use "" or '. Some systems add a backslash while some don't. See also magic_quotes_gpc.

register globals

The older PHP version uses register globals directive set to "on". It is better that you avoid those and use super globals which look like

$_POST says that variables in that array come from a form.
$_GET says that variables are passed through the URI.
$_SESSION says (more than clear) that variables are in a session.