Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!ingr!
From: rob@b15.INGR.COM (Rob Lemley)
Newsgroups: comp.unix.questions
Subject: Re: unix file structure (or lack of same)
Keywords: unix, file, database
Message-ID: <1776@b15.INGR.COM>
Date: 8 Nov 90 22:17:08 GMT
References: <125379@linus.mitre.org>
Organization: Intergraph Huntsville
Lines: 34
th: b15!rob

In <125379@linus.mitre.org> duncant@mbunix.mitre.org (Thomson) writes:

:I understand that, on unix, the file system is designed so that a file always
:looks like a sequence of bytes, with no record structure at all.

:If so, how does one implement an efficient database manager on unix in
:a standard, portable, way?  To be efficient, a database manager needs to
:have random access into files on a record-oriented basis.  It seems to me
:that fseek() wouldn't do the job.  (Am I wrong here?)

yes

:                                                       If unix doesn'`t
:provide a record-oriented view of files, then any database implementation 
:would have to go below unix, and access the mass storage devices directly.

:Is this right?

Absolutely not, in fact, relational databases have been implemented on
UNIX which make extensive use of shell scripts.

A good book on this subject is:

	UNIX Relational Database Management
	(Application Development in the UNIX Environment)
	by Rod Manis, Evan Schaffer, and Robert Jorgenson.
	Prentice-Hall 1988.

Rob
--
Rob Lemley
System Consultant, Scanning Software, Intergraph, Huntsville, AL
rcl@b15.ingr.com    OR    ...!uunet!ingr!b15!rob
205-730-1546