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From: gdavis@primate.wisc.edu (Gary Davis)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: How to find fields that DO NOT contain a string?
Message-ID: <4507@uakari.primate.wisc.edu>
Date: 13 Jun 91 07:45:11 GMT
References: <mike.676744632@ymt>
Sender: news@primate.wisc.edu
Reply-To: gdavis@primate.wisc.edu
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From article <mike.676744632@ymt>, by mike@ymt.com (Michael Czeiszperger):
> Besides the basic telling whether a field does or does not contain
> a certain string, I'm also looking to find a way for the user
> to implement complicated searches without scripting.  In a videotape
> collection stack for instance, the user might want to find all
> videotapes released by TouchStone Pictures between 1989-1990 that 
> are under 2 hours long.  Writing a script won't work because the
> search criteria would change each time.

There are various ways to set up forms which a user could use to
set up complicated queries.

One way is to have a card with the same fields as occur on the regular
collection cards. In your example, the user could just type something
like "TouchStone Pictures" or "=TouchStone Pictures" or "<>TouchStone
Pictures" in the "Producer" field and "< 2" in the Length field. The
search script would use the values in the fields to carry out the
search. 

Another approach is to use popup menus to supply the couplers: "is",
"is not", "contains", "less than", etc, so the user doesn't have
to know what to type in the fields.

The scripting to carry out a search based on the entries in the search
card can get somewhat complicated, but needn't be too bad. One way
is to use "mark cards where" followed by a statement containg all the
conditions, such as,

     mark cards where field "Producer" = "Touchstone" and field "Length"
     < 2

Instead of actual values in the statement you would use variables
set from the fields on the search card.

It may be more efficient in many cases to first "find" the cards where
"Touchstone" is in "Producer" then check on the other conditions. Like
this:

     put "Producer" into fieldToSearch
     put "Touchstone Pictures" into whatToFind
     put 2 into condition
     put "<" into comparisonOperator
     put "Length" into theField
     -- get these from the search card

     put "field" && theField && comparisonOperator && condition
          into conditionStatement
 
     unmark all cards
     mark cards by finding whatToFind in field whatToSearch
     unmark cards where value of conditionStatement is not true

     -- the conditionStatement could obviously be more complicated

If you want to browse through cards rather than mark them all first,
it would probably better to do a standard "find" followed by a check
on the other conditions

on goToNextCardMeetingCriteria

     repeat
          find whatToFind in field whatToSearch
          if the result is not empty then exit repeat -- exit if not found
          if value of conditionStatement then exit repeat

          -- to avoid an potentially infinite loop you would
          -- also need something like this
          if firstCardFound is empty then
               put number of this card into firstCardFound
          else
               if number of this card is firstCardFound then exit repeat
          end if
          -- firstCardFound would need to be a global and to be
          -- set to empty before entering loop
     end repeat

end goToNextCardMeetingCriteria


You might also want to look at the commercial product "Reports 2.0." It
provides easy to use and fast methods for carrying out searches of
essentially arbitrary complexity.

Gary Davis