On implementing temporal coalescing in temporal databases implemented on top of relational database systems

A feasible way of implementing a temporal database is by mapping temporal features onto a conventional commercial database management system. In this paper an analysis of different possible ways of implementing coalescing operator of temporal databases by mapping the temporal data model into the underlying relational model followed by Oracle is done. The temporal time-stamps, implicit in the temporal database, are represented as explicit attributes. The advantages of the two methods of implementing coalescing operator in this work are they are based on currently available standards and there is no requirements for making any extensions to the existing standards other than adding explicit attributes for the implicit attributes of the temporal data model. One strategy is based on SQL: 92 standards and another one is based on functions provided by SQL 2003 approach. A comparative study shows the method based on SQL 2003 approach is better in performance than the other method.