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.
This is the first comprehensive survey of the field of constraint databases, written by leading researchers. Constraint databases are a fairly new and active area of database research. Their ability to deal with infinite sets makes them particularly promising as a technology for integrating spatial and temporal data with standard relational databases. Constraint databases bring techniques from a variety of fields, such as logic and model theory, algebraic and computational geometry, as well as symbolic computation, to the design and analysis of data models and query languages.
This is the first comprehensive survey of the field of constraint databases, written by leading researchers. Constraint databases are a fairly new and active area of database research. Their ability to deal with infinite sets makes them particularly promising as a technology for integrating spatial and temporal data with standard relational databases. Constraint databases bring techniques from a variety of fields, such as logic and model theory, algebraic and computational geometry, as well as symbolic computation, to the design and analysis of data models and query languages.