In this work we establish and investigate connections between causes for query answers in databases, database repairs with respect to 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 are interesting per se. They also 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.

Additional Metadata
Keywords Causality, Consistent query answering, Diagnosis, Integrity constraints, Repairs
Persistent URL dx.doi.org/10.1007/s00224-016-9718-9
Journal Theory of Computing Systems
Citation
Bertossi, L, & Salimi, B. (Babak). (2017). From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back. Theory of Computing Systems, 61(1), 191–232. doi:10.1007/s00224-016-9718-9