Btrieve does not have a concept for allowing multiple different record schemas within a single table, within a sqlable FairCom RTG table. Through the use of the <filters> element, a FairCom RTG user may utilize this advanced feature within c-tree, known as Multi Record Type (MRT) Tables (or "Virtual Tables"). For more information, see FairCom DB API Virtual Tables on the Technical White Papers page of the FairCom website. Please contact FairCom for details if you have use for this feature.