Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!mg2n+
From: mg2n+@andrew.cmu.edu (Martin G. Greenberg)
Newsgroups: comp.lang.pascal
Subject: Re: Deleting records from TYPED file
Message-ID: <sYzHNmO00XcAQ3wUUA@andrew.cmu.edu>
Date: 31 Aug 89 13:45:22 GMT
References: <833@cbnewse.ATT.COM>
Distribution: usa
Organization: Class of '91, Carnegie Mellon, Pittsburgh, PA
Lines: 20
In-Reply-To: <833@cbnewse.ATT.COM>

A bunch of other people and I are involved in a similar project
involving a database, and you have basically two
ways to accomplish add, delete, etc. on  a  typed file.

     1) The method mentioned in the original message. This is probably
the most straight forward, but if
	the database is very large, it is very slow and you can run out of disk
space at times.

     2) Take advantage of TP's allowing you to SEEK positions in a file.
This way you can do bump everything
	down and add the new record, or bump a section of the file back
(over-write the record to delete) and
	then TRUNCATE the file so that it is one record shorter.

This all assumes that you actually want to remove the record and not
just use a flag to mark it, or some such
scheme.

            								MGG