I am talking about designing the control system.
No one makes a perfect design at first go. Devices are deleted and others
added. Until the end of the design stage the numbers need to be sequential
with no gaps. After the design the numbers of each device are static and new
devices are added to the sequence or fill in for abandoned devices - but
that is another, separate problem.
But that is beside the point. What I am looking for is a gapless sequence
generator which has the ability to justify for deletions as well as
additions.
What I am looking for is a very simple adaptation of the serial function.
All that I need it to do is to justify for design changes and not care that
if it is reassinged to a different device. The fact that a particular device
may, by happenstance, change it's assigned number - once twice or multiple
times, during the design stage, is of no consequence - as long as the
totallity of numbers assigned are sequential and gapless.
Bob
----- Original Message -----
From: "Berend Tober" <btober@seaworthysys.com>
To: "Bob Pawley" <rjpawley@shaw.ca>
Cc: "pgsql general" <pgsql-general@postgresql.org>
Sent: Monday, December 04, 2006 7:15 PM
Subject: Re: [GENERAL] PG Admin
> Bob Pawley wrote:
>> Your missing the point.
>>
>> I am creating a design system for industrial control.
>>
>> The control devices need to be numbered. The numbers need to be
>> sequential. If the user deletes a device the numbers need to regenerate
>> to again become sequential and gapless.
> Could you explain what it is about industrial control that requires the
> reassignment of numbers? Seems to me to make for confusion because over
> time, you then have a particular instrument referred to by different
> identifiers. So if you had other data, such as written logs, shop floor
> design diagrams, or other data not included in the data base, for example,
> you'ld have the problem of keeping track of which instruments were really
> being talked about because the names (identifying number, that is) keep
> changing.
>
>
