Time in object databases
Niki Pissinou · University of Southern California Digital Library · 2017
This dissertation identifies, explores, and provides an approach to handling temporal information in object databases. The research specifically involves the design, development and experimental demonstration of a model that integrates time with object databases. This model is the first step towards the synthesis of an integrated object model that supports the temporal aspects of data modeling in addition to the structural and dynamic ones. We study the semantics of time in the context of object databases and identify the temporal aspects of objects and changes to existing notions of temporal data that are necessary because of the transition from the relational to the object model. Our approach leads to the precise characterization of the properties of temporal objects and provides a means of augmenting the data modeling power of the object model, particularly versions, with temporal modeling concepts. To provide a specific context for our approach, we define a framework for a simple temporal object model. This model addresses temporal problems at the finest possible level of data granularity, viz., the object level. The model provides a user with the basic primitives for temporal object definition, manipulation and retrieval. A set of generic temporal constraints is also defined. The primitive operations of this model may be used as the basis for the specification and stepwise development of database models and database systems of increasing complexity. To demonstrate this, we concentrate on extending a specific rich, extensible object database model to incorporate our new notions. An experimental database system prototype has been implemented for validation. The approach to temporal object databases devised here can be utilized in several contexts. In particular, these temporal object notions can be applied to the problem of object and schema evolution. One result of this should be insight into dealing more effectively with the integration of version databases with temporal databases. The class of application environments for which our model and approach are suitable and useful includes time-dependent applications or systems that require some form of action, such as design engineering, office information, medical information, and artificial intelligent systems. (Copies available exclusively from Micrographics Department, Doheny Library, USC, Los Angeles, CA 90089-0182.)