Applications of Finite Differencing to Database Integrity Control and Query/Transaction Optimization

Koenig and Paige have presented a view maintenance strategy based on finite differencing for explicitly storing the values of database views, and updating these values whenever parameters on which they depend are modified. Examples were given that illustrated how this view maintenance strategy could be used to monitor integrity constraints. In this paper, we extend that idea to demonstrate how a DBMS can automatically define its own views that will be maintained efficiently by differencing. Based on this approach, we define a new class of deferred integrity constraints that can be monitored efficiently. In particular we show that the computational cost of each block of constraint monitoring code introduced within the original unmonitored code is bounded by a constant. It is also shown how this approach provides a simple and unified solution to the problem of integrity control and query/ transaction optimization.