Statice limitations

[RDP@ALAN.kahuna.decnet.lockheed.com (Robert D. Pfeiffer)]

    Date: Wed, 27 Jun 90 16:31 CDT
    From: lgm@iexist.att.com

    Our group is investigating the applicability of Statice to our project
    (a switching system prototype).  Outside of the obvious objection that
    Statice is not (yet?) integrated with CLOS, we are also concerned about
    the limits it imposes on database update - or more correctly, the
    information lost when certain kinds of updates occur.  In particular,
    the inability to modify an entity type's inheritance lattice (without
    deleting all existing entities of that type) is a serious restriction in
    comparison to the redefinition freedom that Flavors itself possesses.
    Has anyone found a way to loosen this restriction, or has Symbolics
    promised to loosen it in a coming release?


	    Lawrence G. Mayka
	    AT&T Bell Laboratories
	    lgm@iexist.att.com

    Standard disclaimer.

I haven't seen a reply to this yet so I guess I'll jump in.

My disclaimer:  I'm not speaking for Symbolics -- I'm just another
customer passing along my understanding of the current situation.  If
the following info is wrong, it's my fault.  (If anyone from Symbolics
wants to correct anything I say with the "official" story, I would be
very happy to see it.)

The "Statice/CLOS issue" should be resolved in Genera 8.1.  Statice will
actually continue to be implemented in Flavors as it is now.  So entity
handles will also continue to the Flavor instances.  The thing that will
change to resolve this situation is better integration of Flavors and
CLOS.  In 8.1 CLOS methods will be able to specialize on Flavor
instances.  This will solve the problem for me and, I would guess, the
majority of customers.  A potentially still open issue is that CLOS
classes still will not be able to build on Flavors (or vice versa).

As to the deficiency with Update Database Schema, it is now clear to me
the the right people inside Symbolics understand and acknowledge that
there is a problem.  I'm sure that if/when they decide to address this
issue, they will do a good job of it.  I personally haven't heard any
dates committed to and I agree that your concerns in this area are valid
if you need the ability to preserve data in the face of schema updates
(as I do).  I haven't yet explored trying to "roll my own" functionality
to address this so I have no idea how hard it would be to do as a
customer.

BTW: In case you haven't heard, a major piece of good news at the SLUG
conference came in the form of Ken Tarpey's announcement the "Statice
runtime" will be bundled into Genera 8.1.  In other words, you still pay
extra to develop Statice-based applications but the customers of your
application will be able to use Statice "for free" (if you are
delivering in Genera, this is).  For the situation here, Symbolics has
implemented an ideal pricing strategy.