How to automatically log changes to a field without setting up Change Log Entries in Business Central

In Business Central you can set up Change Log Entries to log insert/modify/delete events for all the fields in all the tables. But can you do this automatically in the code without even setting up the Change Log Entry? It is quite easy actually. Lets say we want to log the change every time someone updates Payment Reference on the Posted Purchase Invoice. We would then create a procedure and attach it to the Purch.