Trigger function on editor update/create/remove

Good morning

Looked through the API but couldn't find a hint how to add a custom function in case a row is created, updated or removed...must be pretty simple I guess (o;

I have two tables, one with orders on top, and one with editable rows at bottom showing the order items...so if I add/change/delete a row belonging to an order, the orders table should be updatd/reloaded as the total amount changes.

thanks in advance
richard