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Archiver > TMG > 2002-04 > 1017948330


From: "Darrell A. Martin" <>
Subject: Re: [TMG] Attaching Exhibits
Date: Thu, 04 Apr 2002 13:26:24 -0600
References: <5.1.0.14.2.20020403142731.02ca1888@pop3.norton.antivirus>
In-Reply-To: <memo.20020404191240.54021A@macmcd.compulink.co.uk>


At 07:12 PM 4/4/02 +0100, Mac McDonald wrote:
>[snip]
>However, as I understand it you still need to define a new exhibit within
>TMGW for each person/event that you wish to link to the external file. The
>external file is then linked to the newly defined exhibit thus you aren't
>able to link an external file directly to a number of people/events as you
>have to have it linked to a separate exhibit each time. Or am I missing
>something?
>
>Is there any reason why there should be such a restriction? For example I
>may wish to link an image of a marriage certificate to the actual marriage
>event and to the birth events for the bride and groom. Or I may wish to
>link a group wedding photo to each person within the photo. To do either
>of these I would have to define the same exhibit a number of times. I
>would prefer the flexibility to be able to link the same exhibit to a
>number of events as it would save considerable duplication.
[snip]

Hi, Mac:

The way TMG works right now, an external exhibit is just a type of
information ABOUT a "thing" (individual, tag, source, repository) and not
really a "thing" in its own right. This is true although there is a
separate file (the "*I.DBF" file) that holds information on the exhibit.
The problem is, each record in this file includes information specific to
the one "thing" to which it is linked; field RLTYPE says what *type* of
"thing" by record type, field RLNUM says which *specific* "thing" of that
type by record number. That eliminates the possibility of portability. To a
database professional, the difficulty comes from the data not being
"normalized" (although that is an ideal, not a rule, and often has to be
ignored for the sake of performance, etc.).

I agree that defining an exhibit, whether internal or external, as a
"thing" in its own right, and then allowing other "things" (individuals,
tags, sources, places -- repository or not) to link to it, would be good.
But the programming effort required would be non-trivial, and would involve
significant changes to the database structure. Maybe BobV. and Co. will
surprise us, and it will be in v.5.

Darrell


Darrell A. Martin
a native Vermonter currently in exile in Addison, Illinois



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