Querying Multiple Temporal Granularity Data

Managing and querying information with varying temporal granularities is an important problem in databases. Although there is a substantial body of work on temporal granularities for the relational data model [11], a comprehensive framework is lacking for the object-oriented paradigm. To the best of our knowledge, a formal treatment of temporal queries with multiple granularities has not been considered in the literature. In this paper we make a step in this direction. We formally introduce the syntax and semantics of expressions involving data with multiple granularities, comparison between data with different granularities, and conversion of data from one granularity to another. We believe that this is an important step towards the development of an object-oriented query language that supports multiple granularities.