A Strategy to Revise the Constraints of the Mediated Schema

In this paper, we address the problem of changing the constraints of a mediated schema M to accommodate the constraints of a new export schema E 0 . We first show how to translate the constraints of E 0 to the vocabulary of M , creating a set of constraints C 0 in such a way that the schema mapping for E 0 is correct. Then, we show how to compute the new version of the constraints of M to accommodate C 0 so that all schema mappings, including that for E 0 , are correct. We solve both problems for subset and cardinality constraints and specific families of schema mappings.