RE: Separation of Presentation, BL, and I/O Tiers

Paul,

In our case it cut down on errors drastically. I don't have hard
numbers, but after implementing a big project that supports
hundreds of database files and users our users reported
almost no bugs during the implementation. That was mostly
due to database layer imposing rules and the high degree
of code reuse. That project took a long time because we
had to build from the ground up. That is why projects like the
iSeries-toolkit

After implementing this across the board, we acquired a new
company. The same people who had estimated projects in
the past went out and built a list of new business requirements.
Their estimate, based on the old single-tier design was that
the enhancements would take about 4 months. Everyone
was happy with the estimate. It only took about two weeks,
which even surprised our developers.

David Morris

>>> paul_nicolay@merck.com 04/11/02 08:36AM >>>
Hi,

I always find this an interesting topic, but first of all I would like
to
know if it solved peoples problems, made life/coding easier, gave
better
performance... and has it ever been used to replace the presentation
layer
with something different (and when you did, was the separation enough,
or
did it require additional changes) ?

I'm sometimes amused when I see that people have changed a single line
of
coding (a CHAIN for example) by 150 other lines that actually do
nothing
more than the CHAIN did originally.

Kind regards,
Paul

PS. I developed a multitier structure myself... but I like to play the
devils advocate in these kind of discussions :-)