What is the perceived wisdom about where to put business rules for a
simple app? (Into the database or the front end?)

I'm planning a commercial Win32 (Firebird) database application which
will mainly be used as a single user standalone program, with a small
percentage of users using a networked workgroup version, so this is
unlikely to ever need 3 tier architecture.

Is it better to put maximum "intelligence" into the DB in the form of
referential rules, sql procedures and triggers etc, or should this be
mainly in the (Delphi)front end?

I'm concerned about:

1. Protection of the intellectual property.
2. Ease of design & maintenance.

Thanks in advance for any guidance.