Re: RPG easier/harder to use than other languages?

"hierarchically-structured" is correct. Exchange data as XML or JSON or
just plain text strings.

Yes, I agree.

Business logic should reside on the IBM i. Putting business logic in GUI
screens is nuts.

Yes, I agree. Putting business logic in business objects that are running
in an address space that is separate from the address space of the database
is, well ... (I'm trying to think of a word that is more diplomatic than
"nuts").

Your "Returning to the idea of deploying web services" are you saying they
are bad idea or a good idea?

In comparison to stored procedures, web services are a good idea,
unequivocally. You pointed out the limitations of stored procedure
interfaces (parameters) and only tabular result sets. I pointed out the
difficulty in securing ODBC interfaces.

Stored procedure interfaces are like the Original Program Model - just one
procedure interface per program. IBM i supports an ILE model now, where any
number of procedures may share state that pertains to a service program.
Web services can adopt the new model.

You have the same problem with web services. You get the web service
request to the server. Now what do you do with it? How do you invoke the
business logic?

The answer to that question gets more entailed and interesting. One needs
some infrastructure to support request processing. Some requests may best
be handled by stateless processes, others by statefull processes. You may
need some logic to dispatch requests to the right components.

The implementation of data validation, referential integrity constraint,
and most business rules should be implemented in connection with DB read,
write, update, and delete events (i.e. triggers), in my opinion.