>>>Thanks a lot in advance.
>>
>>I would use RI even for the simplest of applications - it is easy to use, and it does give you some advantages (data integrity, simplification in some cases through cascading delete).
>>
>>Especially for more demanding applications, I would ADDITIONALLY put validation rules to do some checks before RI kicks in; this is to avoid the user getting unintelligible (for him) messages like "trigger failed".
>
>BTW, do you think I'm OK using native RI?

Yes. Other programs like TaxRI give you additional benefits, but that might not be relevant for a small system.

> And how should I easily move my database changes without using SDT?

Personally, I keep an empty copy of the database, and I have a program that basically does an APPEND FROM for each table, from the user data to the empty structure (which is in a temporary directory, of course).

I can't publish it here, because it relies heavily on VFX functions, but perhaps you can do something similar.

Note that if there is a parent-child relation (and if there is an "R" in the third part of RI restrictions), the parent table has to be copied before the child table.