🚀 go-pugleaf

A couple of thoughts on database implementation questions for hypercard, 
especially as relates to converting an existing dBase application.

1.  Entry validation can be done with the closeField message in the field's
script:

on closeField
  if <validation expression> then
    answer "error msg" with "Ok"
    click at location of the target
  end if
end closeField

2.  You probably want to do relational databases as one stack.  Just put
each separate file into a different background.  Then navigating and 
extracting data doesn't cause endless stack open and closes.  One to one
links are just buttons that take you to the right background. You could 
even have the closeField message create the button script and linked card.

3.  On the issue of "what kind of db application is HyperCard good for?" I
suspect that you want to think "HyperCard" when the application tends to 
be a lookup single or few record type activity, rather than a "do some
action on a 50% subset of the cards" kind of thing.  Not that Hypercard 
wont do the latter, but it just doesn't seem to be as efficient at this 
kind of thing as traditional databases are.  Eventually, I imagine we will
be able to use HyperCard as a front end processor to other databases for
answering questions like "how many of my 10000 employees took vacation 
last month".
                              Dan Graifer
                              graifer@net1.UCSD.EDU
Disclaimer: Nobody ever listens to me anyways; Why should they start now?