Efficient Integrity Checking for Databases with Recursive Views

Efficient and incremental maintenance of integrity constraints involving recursive views is a difficult issue that has received some attention in the past years, but for which no widely accepted solution exists yet. In this paper a technique is proposed for compiling such integrity constraints into incremental and optimized tests specialized for given update patterns. These tests may involve the introduction of new views, but for relevant cases of recursion, simplified integrity constraints are obtained that can be checked more efficiently than the original ones and without auxiliary views. Notably, these simplified tests are derived at design time and can be executed before the particular database update is made and without simulating the updated state. In this way all overhead due to optimization or execution of compensative actions at run time is avoided. It is argued that, in the recursive case, earlier approaches have not achieved comparable optimization with the same level of generality.