The Processing Strategy for the NF2 Relational FRC-Interface
Timo Niemi (1) and Kalervo Järvelin (2)
(1) Department of Computer Science
(2) Department of Information Studies
University of Tampere
P.O.Box 607
FIN-33101 TAMPERE, Finland
Information & Software Technology 31(2), 1995, in press
Abstract
The idea of the frc (form-relations-conditions) - interface is to reduce the user effort in the NF2 (Non-First-Normal-Form) relational query formulation considerably. In the frc-interface the user only describes the structure of the result NF2 relation in a straightforward and intuitive way without specifying in any way how the result NF2 relation is derived from the source NF2 relations. The lack of explicit restructuring expressions from the frc-interface means that query processing must be based on a different approach than that used in query languages (e.g. the SQL extensions made for the NF2 relational model) in which the user specifies the needed restructuring among data explicitly. In this paper we introduce our query processing strategy of the frc-interface which has been implemented in Prolog. Its kernel is a calculus consisting of two constructors (for concatenation and relation construction of NF2 objects). By applying these constructors recursively to atomic-valued attribute representations, any NF2 relation can be constructed. Our calculus-based approach affords the possibility of performing several operations at the same time which gives a good starting point for efficient implementation. In the paper the optimization process used to manipulate several NF2 relations is described.
Keywords: NF2 relational model, User interface, Query processing, Logic programming, Prolog-based knowledge representation
Return to Kal's home page.
Return to Kal's publication list.
Paluu Kallen kotisivulle.
Paluu Kallen julkaisuluetteloon.