Find Candiate Keys - is there a short cut?

From: Mike M <mike.m.news_at_googlemail.com>
Date: 3 Mar 2007 08:19:32 -0800
Message-ID: <1172938772.027328.258740@64g2000cwx.googlegroups.com>

Hi,

I'm wondering if there is any tip or trick how to find ALL candidate keys (CK) for a relation and its FDs, w/o using kind of "brute force" mechanism and trying whether a certain attribute (or composites of attributes) is CK?

Eg, if there is a relation R=ABCDEFG with following dependencies: F={AB-->CD, DE-->AB, AC-->F, BF-->EG, E-->C, G-->H, H-->BF}

I found {A,B}, {A,G}, [A,H}, {D,E}, {D,G}, {D,H}, and {B,D,F} as CKs. I used brute force taktic to get them, but it took me quite a while - and if I don't want to go through all possibilities of composed attributes of R, I'm not even sure whether this list is exhaustive (to my knowledge...).

Sure, finding eg CK {A,B} eliminates other possibilities containing A and B. Still, it just seems not to be the best way. Is there any other?

Thanks for help!
Mike Received on Sat Mar 03 2007 - 10:19:32 CST