Форумы / Cotonti / Development / Plugin which adds a random value to the database on each page load

Read extensions/extdevguide and try to create a simple plugin myplug with two files 1) myplug.setup.php 2) myplug.global.php in his us hook "input" or "global" with your needed code. Then your code will be attached in common.php (will load with ever page request) but common.php not be hacked and after upgrades your code be will work