Hypothetical Temporal Queries in Databases.
Marcelo Arenas, Leopoldo Bertossi · 1998
This paper considers the problem of posing and answering hypothetical temporal queries to databases. The queries are hypothetical in the sense that we pose a query to a virtually updated database, and the query is answered on the basis of the initial, physical database and the list of transactions that virtually update the database. The queries are temporal in the sense that they refer to possibly all the states along which the database evolves from the initial database and the final virtual state. The possibility of answering such queries relies on a specification of the dynamics of the database augmented with a specification of the dynamics of auxiliary tables that have their origin in the temporal subformulas of the query and encode the history of the database. Queries are posed in first order past temporal logic. These functionalities are implemented in SCDBR, an automated reasoner for specifications of database updates. Although we concentrate mostly on relational databases, the m...