At 02:34 AM 1/25/2004, David Johnson wrote:

>All current relational DBMS are ultimately based on the same ISAM
>technology, so the query optimization and hardware selection are the two
>keys to performance.

That seems like a pretty serious generalization. If you mean that all
current relational databases use indexes and can scan tables serially,
then I guess I agree. But I've never seen an ISAM system that implements
multi-generational concurrency. Perhaps I'm behind on my reading about
ISAM (likely, in fact) but the ISAM systems I'm familiar with store their
data as the leaf-level data. Some databases do that, many do not.
Postgres has some very interesting features that I've never seen in an
ISAM system. So does Firebird, even without considering such frivolity
as views, selectable stored procedures, and constraints.

Regards,


Ann