SQL/XNF - processing composite objects as abstractions over relational data

Abstract

Complex applications, such as design applications, multi-media applications, and even advanced business applications can benefit significantly from a database language that supports composite (or complex) objects. Usually such data is inter-related with the data used by traditional applications, such as accounting, ordering, bill of material, and repair and maintenance tracking. Consistency of such data is of utmost importance in applications such as those of aerospace. Hence, sharing of the data among traditional applications and composite object applications is important. Our approach, called SQL Extended Normal Form (short SQL/XNF or XNF) enhances relational technology by a Composite Object facility, which comprises not only extraction of composite objects from existing databases, but also efficient navigation and manipulation facilities provided by an appropriate application programming interface. The language itself allows sharing of the database among normal form SQL applications and composite object applications. It provides proper subsetting of the database and subsequent structuring exploiting subobject sharing and recursion, all based on its powerful composite object constructor concept, which is closed under the language operations. XNF is integrated into the relational framework, thus benefiting from the available technology, e.g. relational engine, query optimization. Currently, a major portion of SQL/XNF is operational in Starburst extensible database system at IBM Almaden Research Center.