An improved algorithm for the incremental recomputation of active relational expressions
Timothy G. Griffin, Leonid O. Libkin, Howard W. Trickey · IEEE Transactions on Knowledge and Data Engineering · 1997
Qian and Wiederhold (1991) presented an algorithm for the incremental recomputation of relational algebra expressions that was claimed to preserve a certain minimality condition. This condition guarantees that the incremental change sets do not contain any unnecessary tuples; so, redundant computations are not performed. We show that, in fact, their algorithm violates this condition. We present an improved algorithm that does preserve this notion of minimality.