Re: Triggers or Journals?

["R. Bruce Hoffman, Jr." <rbruceh@xxxxxxxxxxxxx>]

-----Original Message-----
From: Graap, Ken <keg@exchange.gasco.com>
To: 'MIDRANGE-L@midrange.com' <MIDRANGE-L@midrange.com>
Date: Thursday, March 29, 2001 12:22 PM
Subject: RE: Triggers or Journals?


>>IBM is going gung ho with triggers for editing on their files.
>
>I wonder why there isn't a broader use of DB Referential Constraints in
>DB2/400? Moving editing logic into the database and out of application code
>sure seems to make sense. Is anyone moving their DB editing logic into
>DB2/400 via DB Constraints?


DANGER WILL ROBINSON!

can of worms ahead....

Retro fitting referential constraints is a nightmare. Most 400 databases are
not new, they have been around for a while. Usually just long enough for a
programmer to quickly add some fields to different files without considering
normal forms and the meaning behind it.

That makes for significant loss of sleep later.

It makes sense, but only if planned for in advance. Build a new database?
Then yeah, no problem. Use a good design tool (like ERWin or ERStudio) and
you can prove out the constraints as you design and build. Then you can get
some sleep.

I have added constraints to existing databases, and it (so far) has never
been easy. Past design flaws jump out at you at the worst moments.


===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified Specialist - AS/400 Administrator
 -- IBM Certified Specialist - RPG IV Developer

"America is the land that fought for freedom and then
  began passing laws to get rid of it."

     - Alfred E. Neuman


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