Problem with primary key

Hello all, I'm using Informix Server 7.2x. The Informix system table sysconstraints allows me to find out if a given table, say known_table, has a primary key via, for instance, select * from informix.sysconstraints where tabid = tabid_of_known_table Suppose that the above select query indicated that known_table has a primary key. Does anyone know how I can find the column name associated with that key? Any help or suggestion is very much appreciated. Vinhson Email: nguyenv@cognos.com