Where to store common 'global' functions?

If you want them loaded all of the time, you can add them App/Common.php.

If you want them to be available to load just when needed, treat them as a Helper.

You mean just "Extending" Helpers?

You only need to "extend" if they're the same name as another one.

Create a new file for your own helpers. Based on your comment, we'll call it database_helper.php. Store this file at App/Helpers/database_helper.php. Then use [b]helper('database')[b] when you need to load them. Or autoload them per-controller.

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