Model and Algebra of Object-Relation Bitemporal Data Based on Temporal Variables

The processing of temporal data is based on the platform of relational databases mostly, and temporal data model is an important part in the general temporal data model. It is difficult for relational data model to deal with the data which contains the complex type, and the object oriented data model is short of commercial applied basis. There are extensions to the function of objects in most relational databases, so it's not only very necessary but also rather feasible to extend the temporal relational data model to the one based on object-relation. Firstly, working on the data model of temporal-relation, a bitemporal data model on object-relation is proposed in this paper, which may be implemented in current object-relational databases. Secondly, the relationship and the transformation between temporal object-relation and the temporal relation are disussed in the model's framework, which is a fundamental requirement of extending temporal data schema to temporal object-relational data schema. Thirdly, the complex semantics of the temporal variables and the corresponding binding algorithm of the variables are discussed, which is one of the keys for the practical operation of temporal databases. Finally, the temporal algebra operations of the temporal object-relation data with the complex semantics in temporal variables are built, which is a significant for the study of the temporal query algorithm.