[AccessD] Cascade-delete (was: Estimating Help)

John Bartow john at winhaven.net
Wed Feb 5 11:45:00 CST 2003


Hi Gustav,
I quite responding to a thread when it gets too inflammatory. (Plus, Susan
implied that it was getting a bit out of hand.) When things get derisive I
know that no one is going to learn anything. I learned a long time ago that
some people see things in binary tone and some people see them in continuous
tone. I've been working in the computer field since 1979 and while that
certainly doesn't make me an expert at anything it does give me a bit of
experience. Deriding my physical or mental work habits because I have an
opposing view isn't going to change my mind on an issue. Debating and
discussing with someone who is knowledgeable, experienced and of a different
opinion may well expand the possible solutions that my mind can formulate.
The way I look at it there's always more than one way to do anything. To me
its a matter of finding the best solution for each situation. In that
respect, I disagree with people of the binary tone viewpoint - but I still
respect them :o)

As far as cascade delete goes, I tend to agree with many issues covered in
the thread. I do take exception to the word "never". Just as I would
disagree with saying never to bound/unbound forms or natural/autonumber
keys. There is always an exception to every rule so instead I view them as
"guidelines". In the particular situation I sited, I think cascade delete
fits the bill much better than using code or queries to delete the child
records. The parent record WAS able to be deleted by "anyone" using the DB.
The records were used for formulating ideas or "scenarios" and left in the
table to avoid having to recreate the same scenario at a later date. Only 1
would be chosen and used for any particular case. So essentially the records
not chosen could be viewed later and certain parameters could be modified
for more "brainstorming" scenarios, thus preventing the NEED to re-enter of
bunch of mundane detail data. It is one example where using an Access DB is
actually more powerful than some major DBs because I don't have to specify
that every program using the BE DB must write procedures to clean up these
unused child records when deleting a un-chosen scenario. The reality of the
situation is that just because someone has a degree and/or experience using
a GIS doesn't mean they understand relational databases, Access queries or
VB code. Until recently the major GIS platform used in the USA used a flat
file database and an application specific macro language. Now we're pushing
and pulling MBs of spatial data into and out of Access DBs and using VBA!

Cascade Delete certainly can be dangerous but like someone famous once said:
"with great power comes great responsibility"!

John B.
"In Wisconsin, in the winter, in my office, in the basement...
nothing is black and white here."

-----Original Message-----
From: accessd-admin at databaseadvisors.com
[mailto:accessd-admin at databaseadvisors.com]On Behalf Of Gustav Brock
Sent: Wednesday, February 05, 2003 5:55 AM
To: Arthur Fuller
Subject: Re: [AccessD] Cascade-delete (was: Estimating Help)


Hi Arthur

> Speaking only for myself, I use cascade frequently delete, wherever it's
> appropriate. When I began this thread, I didn't mention cascade delete at
> all. I very specifically said "rows disappearing from reports" -- not from
> tables. This was an RI issue, not a cascade issue. However, since I have
> been known to rant, carry on :-)

Hmmm ... nice try. And it brought some relief.

But [picky mode on] you did start the thread - I couldn't read this in
more than one way:

> I didn't mean that the rows were disappearing, but rather that they
> disappeared from reports, since their FK referents were gone. I would
never
> be so foolish as to turn cascade-delete on anywhere in any serious
database
> :-) I restored an old copy with the deleted employees, then imported the
> rows and restored sanity to the db.

/gustav

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