RE: Primary & Foreign key constraints

From: <Colin.Shaw_at_phs.com>
Date: Tue, 23 May 2000 10:19:05 -0700
Message-Id: <10506.106405@fatcity.com>

Rufus:

Whilst I agree that it's a disadvantage not having the RI enforcement at the database, I have worked on quite a few systems that did not. I wouldn't go so far as to call the designer "an idiot", because most, if not all, were legacy systems that had been designed before many databases even *had* RI syntax. They all "enforce" RI by "do-it-yourself" FK/PK lookups (using indices, of course.) It would be a waste of time at this point to put RI on the database(s) because unless the code was substantially modified to remove all the lookups, you would end up doing double the amount of work necessary. Luckily, there are little or no ad-hoc mods (or unrestricted accesses) to these databases. However, I think many programmers like to do the checking "for themselves" probably because they don't trust "the database" or "the DBAs" to do it for them!

Colin.

-----Original Message-----
From: Abdul Aleem [mailto:abchaudhary-ho_at_beaconhouse.edu.pk] Sent: Tuesday, May 23, 2000 12:44 AM
To: Multiple recipients of list ORACLE-L Subject: RE: Primary & Foreign key constraints

To add to what Deepak has said,

There are no merits to this practice. I would say that the person who designs a database without FK and PK is highly unprofessional (an idiot) and has absolutely no idea of RDBMS design. This can lead to current and future problems.

I would suggest to enforce RI constraints at database level at your earliest.

Heavy Front-end, (more network traffic, client machines with good specs.)
Lengthy code, (difficult in locating problems and making modifications)
If someone gains access to the database without front-end, can insert a lot of garbage without much of a hassle.
When you hire new developers they will have to follow the same wrong-practice unless someone takes pain and define RI (Referential data Integrity constraints).
If you try to implement RI, be prepared to get a lot of duplicate records especially in daily transaction tables.

I would appreciate if you could tell what application is that

Hope this helps

Regards,

Aleem

		-----Original Message-----
		From:	Thapliyal, Deepak [mailto:DThapliyal_at_ea.com]
		Sent:	23 May, 2000 11:16 AM
		To:	Multiple recipients of list ORACLE-L
		Subject:	RE: Primary & Foreign key constraints

		Rufus,

		if you try to enforce RI at the app level .. u are looking
in the face of
		increased IO hits as you try to manually force RI rules..
may also lead to
		funny situations (mutating/constraining) as you start
playing with triggers
		trying to accomplish the same. thats all my brain cells
allow me to write at
		this point :-((

		deepAk

		-----Original Message-----
		Sent: Monday, May 22, 2000 10:44 PM
		To: Multiple recipients of list ORACLE-L


		Hi Guru's,

		Will any one tell, if there is any specific advantage if we
don't have
		primary & foreign key constraints at database level. In one
of our major
		applications I have seen, they do not  have primary &
foreign key
		constraints defined at database level, but handled at the
front end level.
		Can anyone tell what could be the merits if any ? 

		TIA,
		Rufus.
		-- 
		Author: Rufus Chinnam
		  INET: rufus.chinnam_at_emirates.com

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		Author: Thapliyal, Deepak
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-- 
Author: Abdul Aleem
  INET: abchaudhary-ho_at_beaconhouse.edu.pk

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Received on Tue May 23 2000 - 12:19:05 CDT