Consistent query answering in databases
ACM SIGMOD Record
The Consistency Extractor System: Querying Inconsistent Databases Using Answer Set Programs
SUM '07 Proceedings of the 1st international conference on Scalable Uncertainty Management
The consistency extractor system: Answer set programs for consistent query answering in databases
Data & Knowledge Engineering
The semantics of consistency and trust in peer data exchange systems
LPAR'07 Proceedings of the 14th international conference on Logic for programming, artificial intelligence and reasoning
Semantically correct query answers in the presence of null values
EDBT'06 Proceedings of the 2006 international conference on Current Trends in Database Technology
| Hi-index | 0.00 |
Databases may not satisfy integrity constraints (ICs) for several reasons. Nevertheless, in most of the cases an important part of the data is still consistent wrt certain desired ICs, and the database can still give some correct answers to queries wrt those ICs. Consistent query answers are characterized as ordinary answers obtained from every minimally repaired and consistent version of the database. Database repairs can be specified as stable models of disjunctive logic programs with program constraints. In this paper, we optimize repair programs, model computation, and query evaluation from them. We make repair programs more compact by eliminating redundant rules and unnecessary programs denial constraints. These results facilitate the application of magic sets techniques to query evaluation in general, and in DLV, a logic programming system that implements the stable models semantics, in particular. We also analyze the implementation in DLV of queries with aggregate functions.