From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back

• DOI: 10.1007/s00224-016-9718-9
• Publication Date: 2016-11-24T21:11:47Z
• Authors: Leopoldo Bertossi; Babak Salimi
• Keywords: FOS: Computer and information sciences; Computer Science - Logic in Computer Science; Computer Science - Artificial Intelligence; Databases (cs.DB); 0102 computer and information sciences; 02 engineering and technology; 01 natural sciences; 004; Logic in Computer Science (cs.LO); causality,diagnosis,repairs,consistent query answering,integrity constraints; Artificial Intelligence (cs.AI); Computer Science - Databases; 0202 electrical engineering, electronic engineering, information engineering; ddc:004

To appear in Theory of Computing Systems. By invitation to special issue with extended papers from ICDT 2015 (paper arXiv:1412.4311)<br/>In this work we establish and investigate connections between causes for query answers in databases, database repairs wrt. denial constraints, and consistency-based diagnosis. The first two are relatively new research areas in databases, and the third one is an established subject in knowledge representation. We show how to obtain database repairs from causes, and the other way around. Causality problems are formulated as diagnosis problems, and the diagnoses provide causes and their responsibilities. The vast body of research on database repairs can be applied to the newer problems of computing actual causes for query answers and their responsibilities. These connections, which are interesting per se, allow us, after a transition -inspired by consistency-based diagnosis- to computational problems on hitting sets and vertex covers in hypergraphs, to obtain several new algorithmic and complexity results for database causality.<br/>