Schema Evolution publication categorizer

Schema evolution occurs frequently in practice. In this paper, we show that the entire schema does not need to be redesigned every time a change is made. We characterize the subschema affected by basic schema operations, which allows us to limit the scope of checking required and have a guarantee of the overall design being correct (safe changes). In addition, we characterize the effects on the actual relations of the addition and removal of constraints. In some cases, relations may have to be added to or removed from the database in order to preserve correctness.