gblee@maui.cs.ucla.edu (06/27/89)
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. --Geunbae Lee,m UCLA-CS-AI.
awd@dbase.UUCP (Alastair Dallas) (06/28/89)
In article <25232@shemp.CS.UCLA.EDU>, gblee@maui.cs.ucla.edu 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... ...description omitted... > 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. > --Geunbae Lee,m UCLA-CS-AI. This may not be more attractive than suggesting a minicomputer, but it's not clear from your posting that you are using the multi-user versions of dBASE III or Paradox. dBASE III PLUS LAN Pack is a separate package you can buy to allow multiple users to access data. dBASE IV comes ready for use on a LAN, but you may have to purchase additional user licenses. Hope it helps. /alastair/
benderly@cs.columbia.edu (Dan Benderly) (06/28/89)
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 Description Omitted ..... Paradox has a network version (at least in 2 it did -- I think in 3 it comes with the single-user package, but you have to buy more lic\scences for multi -user operations). Anyway, Paradox has a co-edit mode, which allows multiple people to access the same data file, and locks users out only when necessary. The screen is updated with thenew data periodically. Dan benderly@cs.columbia.edu
leonard@bucket.UUCP (Leonard Erickson) (06/29/89)
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