An Example of Knowledge-Based Query Processing in a CAD/CAM DBMS
Arnon S. Rosenthal, Sandra Heiler, Frank Manola · Very Large Data Bases · 1984
Queries to part hierarchies in CAD/CAM databases (and structures with similar semantics found in other applications) can be fundamentally different from queries to sets of parts having no underlying structure, and they can raise dif f icult issues in query language behavior and data management. Including explicit geometric informat ion further complicates query processing by adding computational geometry to the list of is sues to be considered. In this paper, we investigate the problems of querying part hierarchies and of using the special semantics associated with such structures to improve query performance and responsiveness to user requirements. In particular, we show how the hierarchy and geometry can interact to improve query processing, and how knowledge about the behavior of attributes stored in the hierarchy can be used to choose appropriate levels of detail for query output. -his research is funded by General Dynamics, Data Systems Division. Permission to copy without fee all or part of this material is granted provided that the copies are not made or diwibuted for direct commercial advantage, the VLDB copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Very Large Data Base Endowment. To copy otherwise, or to republish, requires (I fee and/or special permission from the Endowment. Proceedings of the Tenth International Conference on Very Large Data Bases. 1. Information Model A basic data structure frequently found in databases for computer aided design and computer aided manufacturing (CAD/CAM) applications is some form of bill-of-materials (BOM). This structure defines the component parts and subassemblies that make up each product being designed or manufactured (an assembly is a part that is composed of other parts). The classic BOM structure has a schema of the form: ------------------------PART 1 PARTID 1 COST I . Moreover, such structures are not confined to CAD/CAM applications. Examples of other applications exhibiting similar structures include: Singapore, August, 1984