Re: Using joinfiles w/ large databases, referential integrity

Hi,

in germany we say: was der Bauer nicht kennt, frisst er nicht in english something like that: what the farmer doesn't know, he will not eat

Dieter

Bob Hairgrove wrote:

> Hi,
>
> I do a lot of database development, but haven't worked with DB2 on
> AS/400 too much since most of my previous work has been in Oracle and
> MS-related stuff on Windows.
>
> We are doing some work now for a company which gets their data from a
> different company which has a large database on DB2 running on AS/400
> or some other IBM mainframe (I don't know how large, but it is large
> .. presumably something in the terabyte range).
>
> Everything is in flat files, no FK constraints, PK constraints are
> only on paper, nothing is journalled, etc. All referential integrity
> and business rules are apparently implemented by server procedures,
> and the data is only in 1st normal form (at best).
>
> Since we only read their data, it doesn't really matter to us as long
> as they keep it consistent. Just out of curiosity, though, I asked one
> of their developers why there are no constraints in the database and
> the response was that it is apparently quite painful to rebuild the
> joinfiles (i.e. constraints) with a large database on AS/400 if they
> ever "break" (whatever that means, "painful" meaning a downtime of
> several days).
>
> So my question to you is: How many people work with such large
> databases and still use constraints with referential integrity
> enforced through joinfiles? Is there another possibility? Or is it
> just too impractical above a certain size? What limits are considered
> too large for DB engine-level RI in the AS/400 and mainframe world?
>
> As I had always been taught to normalize and use sufficient
> constraints with RI, I must admit that I had trouble getting used to
> the idea that many serious applications don't use them at all.
>
>
> Bob Hairgrove
> rhairgroveNoSpam_at_Pleasebigfoot.com
Received on Sat Sep 21 2002 - 18:57:53 CEST