Path: utzoo!utgpu!watmath!xenitec!timk
From: timk@xenitec.uucp (Tim Kuehn)
Newsgroups: comp.databases
Subject: Re: dBase/Clipper
Summary: iif helps out
Message-ID: <1989Aug8.130848.15052@xenitec.uucp>
Date: 8 Aug 89 13:08:48 GMT
References: <1989Aug4.172532.10732@maccs.dcss.mcmaster.ca>
Reply-To: timk@xenitec.UUCP (Tim Kuehn)
Distribution: na
Organization: Xenitec Consulting Services, Kitchener, ON
Lines: 37

In article <1989Aug4.172532.10732@maccs.dcss.mcmaster.ca> pjr@maccs.dcss.mcmaster.ca (Patrick J. Ryan ) writes:
>In trying to run some dbaseIII+ programs using clipper, I have
>encountered a problem with the following example:
>
>The database is a baseball team roster which I am trying to order
>by batting average.  Thus I have the statement
>
>INDEX ON (1-H/AB) TO BA
>
>(H and AB are numeric fields standing for hits and at-bats respectively)
>dbase III+ happily constructs the index, even when some of the records
>have a 0 value for AB.  When the list is printed out using the index,
>the ratio H/AB is printed out as ****** but occurs at the bottom of
>the list, as if it were 0.
>
>Clipper compiles and links ok but when the program runs, it hits a
>division by 0 error.  This happens even when there are no records
>having AB = 0.
>
>Does anyone have an idea of why this occurs and/or how to avoid the
>problem?  Thanks. 

dbase III+ allows divide by zero and doesn't complain? Sheesh!

For your clipper index I suggest:

Index on iif(ab=0,0,1-h/ab) to ba

(you can replace the ',0,' with any appropriate number you like).

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