For several reasons a database may not satisfy certain integrity constraints (ICs). However most likely most of the information in it is still consistent with the ICs; and could be retrieved when queries are answered. Consistent answers with respect to a set of ICs have been characterized as answers that can be obtained from every possible minimal repair of the database, where the repairs are obtained by deletions/insertion of whole tuples. In this paper we study the problem of fixing (repairing) databases by updating numerical attributes of tuples with respect to denial constraints. We introduce a quantitative definition of database fix, identify relevant tractable cases and introduce approximation algorithms for some of those that are intractable.
['Leopoldo Bertossi', 'Loreto Bravo', 'Enrico Franconi', 'Andrei Lopatenko']
Fixing inconsistent databases by updating numerical attributes