Extending Database Management Systems for Engineering Applications

Abstract

During the design of a manufactured component, large amounts of information pertaining to all aspects of the design must be stored, accessed, and operated upon. A database management system (DBMS), composed of a central repository of data and the associated software for controlling accesses to it and operations on it, provides one way to uniformly store, manage, and use this information. This paper presents a framework for an extension to relational database management systems that combines a set of engineering constraints with a database of engineering data items. The representation requires a database that is able to store all of the data normally associated with engineering design as well as the constraints imposed upon the engineering design process. A powerful and flexible constraint processing system is needed to adequately ensure that engineering data conforms to the limitations imposed upon it by the design process. Such a system must be capable of allowing constraints to be invoked at a variety of times, and provide numerous options for the user when violations are detected. This paper introduces a concept called structured constraints that integrates state- of-the-art advances in DBMSs and current research in engineering constraint processing to further enhance CAD system capabilities. It discusses the extensions to relational database theory that are needed to achieve such a constraint handling capability for mechanical engineering applications. The goal sought is a managed repository of data supporting interfaces to a wide variety of application programs and supporting processing capabilities for maintaining data integrity by incorporating engineering constraints. The Structured Constraint model is a general method for classifying semantic integrity constraints. It is based on the structure of the relational model and is therefore independent of any particular query language. In addition, it is a formalism that possesses conceptual clarity and generality which make it useful for representing and communicating arbitrary constraints. The key contribution of this formalism is its basis for a completely definable implementation of an engineering integrity syste