RE: No primary keys

Yes it is. > -----Original Message----- > From: Woodall Con [mailto:cwoodall@vth.colostate.edu] > Sent: Tuesday, January 09, 2001 1:02 PM > To: Parker, Jack > Cc: informix-list@iiug.org > Subject: RE: No primary keys > > > I heard somewhere that enterprise data replication might require > that all tables involved to have primary keys. Anybody know if that's > true? > > Con Woodall > Colorado State University Veterinary Teaching Hospital > Computer Services > cwoodall@vth.colostate.edu > 970-491-1244 > > > On Tue, 9 Jan 2001, Parker, Jack wrote: > > > > > An excellent point. One great way to improve DSS > performance is to drop > > indices - that may include PKs. > > > > cheers > > j. > > > > > -----Original Message----- > > > From: cedarsiding@my-deja.com [mailto:cedarsiding@my-deja.com] > > > Sent: Monday, January 08, 2001 6:07 PM > > > To: informix-list@iiug.org > > > Subject: Re: No primary keys > > > > > > > > > > > > > you can't even > > > > use referencial constraint (foreign keys) between your > tables if you > > > do > > > > not have primary keys on them. > > > > > > Child tables need no primary key, only parent tables do. > > > > > > > > > > That's why it's strongly recommendated that all tables in your > > > database > > > > model must have a defined primary key. > > > > > > I don't think this is valid generic advice. One should consider > > > whether one needs something before using it, because it does > > > have a cost in both disk space and performance. > > > > > > Primary keys are often vital in "operational" systems, > > > i.e. OLTP or ODS (operational data store) applications. > > > Some DSS applications do not need them, or at least not > > > on all tables. > > > > > > -cs > > > > > > > > > Sent via Deja.com > > > http://www.deja.com/ > > > > > >