The ramification and qualification problems in temporal databases

Abstract. The ramification and qualification problems are two infamous, hard and ever present problems in databases and, more generally, in systems exhibiting a dynamic behavior. The ramification problem refers to determining the indirect effects of actions, whereas the qualification problem refers to determining the preconditions which must hold prior to the execution of an action. A solution to these problems in database systems permits reasoning about the dynamics of databases and allows proving consistency properties. These two problems become increasingly complex in temporal databases and no satisfactory solution has been proposed as of yet. In this paper, we describe these two problems in the context of temporal databases and we propose a solution of polynomial complexity based on the language of the Situation Calculus. This solution extends previous proposals for the solution of these problems in conventional (non-temporal) databases.