In this paper we discuss extensions to the conventional relational algebra to support transaction time. We show that these extensions are applicable to historical algebras that support valid time, yielding a temporal algebraic language. Since transaction time concerns the storage of information in the database, the notion of state is central. The extensions are formalized using denotational semantics. The additions preserve the useful properties of the conventional relational algebra.
ASJC Scopus subject areas
- Information Systems