Xref: utzoo comp.databases:2852 comp.sys.ibm.pc:30846 comp.dcom.lans:3078
Path: utzoo!attcan!uunet!zephyr!tektronix!psueea!parsely!bucket!leonard
From: leonard@bucket.UUCP (Leonard Erickson)
Newsgroups: comp.databases,comp.sys.ibm.pc,comp.dcom.lans
Subject: Re: Concurrency Control in DbaseIII+ or Paradox...
Message-ID: <1512@bucket.UUCP>
Date: 29 Jun 89 06:08:53 GMT
References: <25232@shemp.CS.UCLA.EDU>
Reply-To: leonard@bucket.UUCP (Leonard Erickson)
Organization: Rick's Home Grown Unix; Portland, OR
Lines: 34

In article <25232@shemp.CS.UCLA.EDU> gblee@CS.UCLA.EDU (Geunbae Lee) writes:
<Please consider the following problems:
<We have one file server(ibm ps/2) and two workstations (ibm at and xt) 
<connected using Novel Advanced Netware. The server machine
<is running dbaseIII+ or Paradox. Now, we want our 3 personell 
<simultanously acess the database file on the server and modify it and
<do whatever he/she wants. I know this is the basic concurrency
<control problem in database field. Now the question is
<this kind of job could be done on Pc level. What is responsible for
<this Os/2 on Ps/2, Netware or DbaseIII+ (or Paradox)? Don't
<simply say you have to buy expensive Distributed DBMS or Minicomputer.
<What is the constsructive solution for this problem? Thank you
<for the time and response.

Well, Novell will handle some of it. As for the rest, in dBase you need
to get the Dbase Administrator package, and a Lanpack (this will give
you up to 7 users, each additional pack will add 5).

Now comes the fun part. Rewriting all your programs to use record locking.

I've got no idea how Paradox does (or doesn't) handle file and record
locking, but I'd be willing to bet that it won't recognize dBase's locks.
In my (limited) experience you can't have programs from different vendors
accessing dBase files on a LAN. dBase only recognizes their own locks,
and others (such as Foxbase) only recognize *their* locks. <grrr>

For what it is worth, dBase IV, in spite of it's other shortcomings, *does*
automatically implement record locking. I can BROWse a file and it only
locks the record I'm changing *when* I change it. 
-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short