Object behavior modeling in object-oriented databases

Abstract

Many object-oriented data models emphasize the expression of the structural aspect of objects while leaving the behavioral aspect of objects unorganized until implementation. This may cause an inconsistency between the structural aspect and the behavioral aspect of objects. Moreover, to represent a data model at the conceptual level, they use eigher a diagrammatic notation, which focuses on displaying a conceptual schema that is easy to understand and interpret, or a formal specification language, which focuses on formal and unambiguous specification of the schema, but they do not support both of them together which, we think, is essential. This may cause an impedance mismatch when a model is biased toward one of the two. Two overcome the inconsistency and the impedance mismatch, we propose an object Behavior Modeling for object-oriented database design methodology. Object behavior modeling method can serve as a documentation tool and formal specification as well as a conceptual database model in the database design process. The modeling process is based on the three phases of stepwise refinement: object behavior diagram, object behavior specification, and schema evolution. Object behavior diagram is a diagrammatic notation for gross design of databases. It consists of object diagram which describes classes, attributes, and relationships between classes, and behavior diagram which describes states, events, and the interactions between objects on the basis of object``s life cycle. We provide the notion of behavior abstraction using the concepts of generalization and aggregation to improve the comprehensibility. Object behavior specification is a formal and non-procedural description for detailed design. It consists of object specification which describes the class structure in detail, and behavior specification which describes the semantics of the way a behavior is invoked and operated. As object-oriented database applications constantly require frequent updates...