[AccessD] Aquarium Life

[John W. Colby]

That is an interface question of course.

Strategies:
1) Warn that the new fish doesn't work.
2) Indicate which fish the collision occurs with.
3) Prevent a save if a collision exists.

4) Narrow down the available fish to be selected based on compatibility 
with existing selections.

All strategies have pros and cons.

#1, #2 and #3 are really one strategy.

#4 just works in terms of always selecting only matching fish. However 
it doesn't help in seeing WHY some other fish I want has disappeared, or 
which fish, if deleted, would bring back the one I want.  If #4 is 
selected then some method of seeing collisions with other fish is necessary.

It would be really nice to do something like color code the existing 
records / fields based on the new selection.  I think that Access forms 
allow this in some simple form.  Not sure whether the implementation 
would fit the problem however.  If that could be implemented then a very 
nice visual of mismatches could be seen.

The nice part is that for most of us, the actual number of different 
AquariumFish (records) allowed will be pretty restricted, it's not like 
we have to deal with thousands or even hundreds of already selected fish 
(species).

This is a messy problem IMHO.  You do absolutely want to prevent 
selecting fish that can't co-exist however.  Not a good idea to allow 
selecting a fish that is gonna die in the current environment.

John W. Colby

On 3/4/2015 1:41 PM, Arthur Fuller wrote:
> John,
>
> I never doubted for a second that this would be a problem demanding a
> database-solution. One particular aspect that I'm having trouble with is
> this:
>
> given a selection of fish so far, which all fall within say temperature
> range R1-R2;
> given the desire to select a new fish, whose inclusion might change either
> R1 or R2 or perhaps both, in such a way that Fish1 and Fish6 may no longer
> be able to handle the new temperature range (too cold now or too hot), then
> drop the new one or the other two?
> ​