The master trigger of an application is a hand-written package named `<prefix>_master_trigger`. The business layer calls it for every row of every table, once before and once after the change, with the name of the business object. It is the place for a rule that applies to all tables at once, such as a check whether the current screen may change data at all, or whether the licence covers the change. Where a [[Invantive Studio/Repository/Concepts/Hook Package|hook package]] serves one table, the master trigger serves the whole application.