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From: rahard@eeserv.ee.umanitoba.ca (Budi Rahardjo)
Newsgroups: comp.lang.perl
Subject: need advice - writing a database system
Keywords: database, dbm
Message-ID: <1991May3.093532.19393@ccu.umanitoba.ca>
Date: 3 May 91 09:35:32 GMT
Sender: news@ccu.umanitoba.ca
Followup-To: comp.lang.perl
Organization: Dept. Electrical Engineering, U of Manitoba
Lines: 48


Hi there,
I am in the process of writing a userid database for our computer networks.
We have approx. 17000 users (4 networks and only considering valid userids for
the last 5 years). There are apporx. 30 fields for each record (userid, name,
uid, gid, e-mail, reg.date, expiry date .... etc.)
The objective here is to have unique userids and UIDs. For example
userid will be created if nobody is using it, and the database will
give a new UID. (This brings a policy/question of recycling uid, *sigh*)
Also this database should be accessible only by system administrators of
the 4 networks thru a client program.
I am going to write a database server and client in perl on a networked-Sun.
(actually I have a prototype up and running, but I am not satisfied)

I need suggestions :

1. Would you use a flat file or dbm file for the database ?
2. Would you slurp the whole file ? (considering the number of fields,
   and the size of the database)
3. If I use dbm file (with assoc. array)
   - I'd like to index it with different fields (ie, userid, lastname, uid).
     How do I do this ? (Use different dbm files ?)
   - When I update a record, I want to save it right away.
     Do I have to close the dbm file (dbmclose) and re-open it again ?
     ie. Is there away I can update the dbm file without closing it ?
4. Access to the database by more than one persons at the same time
   is desireable.
   How would you lock the database when you perform critical operations,
   like add a new entry, or updating a record ? (Use perl lock ? or
   just create a file, say  "lock.db", then remove it after you're done ?)
5. Security
   How would you implement security ?
   (Right now I have it setup like pop-mail; after you connect, send an id
   then send a password).
6. Comments ?


Thanks,
-- budi

Note :
- I have tried "jinx", it's too slow, doesn't have a locking facility
  and I don't want the user to be able to change the database structure.
  I wonder if there is an enchanced-jinx ....
--
Budi Rahardjo
<rahardj@ccu.umanitoba.ca>      <rahard@ee.umanitoba.ca> 
Electrical Engineering - University of Manitoba - Canada