Analysis of active database rules behaviour using rewriting logic

Abstract

Integration of activity in object-oriented database systems, through the support of active rules, requires to guarantee certain properties such as termination and confluence. It is necessary in particular to be able to take into account various dimensions of the execution model since these dimensions directly influence termination and confluence. Few studies relating to termination and confluence consider these dimensions. In this paper, we suggest using a formalism based on the rewriting logic to describe an active object-oriented system. We show that the main dimensions of the active rule execution model can be expressed by adding three strategies: activate all the solutions of a subset, choice at more one solution of a subset, reiterate a solution as many times as possible. The problem is then to model the behaviour of a whole system. We suggest distributing the rules into strata. The interest of such a process is that the global strategy which models the behaviour of the system is the concatenation of the local strategies which model the behaviour of the different strata. Three different stratification algorithms are given. The analysis of termination and confluence then rests on the simulation of the global strategy.