Re: Discovering new relationships
Date: 8 Mar 2007 07:30:27 -0800
Message-ID: <1173367826.938515.302300_at_30g2000cwc.googlegroups.com>
On Mar 8, 6:18 am, "Walt" <wami..._at_verizon.net> wrote:
>
> This can be one of the largest issues for "large, shared databases" going
> forward. On the one hand, you want flexibility, so that requirements that
> didn't go into the logical model of prior versions can be accommodated. On
> the other hand you want extreme backward compatibility, so that the
> longevity of the database can be appropriately exploited. The sweet spot on
> the trade-off is difficult to find.
"... so that the longevity of the database can be appropriately
exploited"
to me means that existing software continues to work. Software
contains embedded assumptions about schema that may become
stale, and it would be nice if the software continued to work even
if the schema changes. In other words, decouple releases of
the schema and releases of the software.
One approach to this problem is simply not to do it. Couple to software and the database and change both at once. This is only practical if you control both the software and the database. It sounds bad when you say it but it's not as bad in practice as it sounds.
The theoretical approach that I usually hear mentioned here is views. I have no direct experience with them so I don't have an opinion on how well they work in practice. But the idea is certainly appealing.
Marshall Received on Thu Mar 08 2007 - 16:30:27 CET