Filters








2 Hits in 8.0 sec

Project-Join-Repair: An Approach to Consistent Query Answering Under Functional Dependencies [chapter]

Jef Wijsen
2006 Lecture Notes in Computer Science  
7000 Mons Ed 1962 M 7000 Bergen An 1964 F 7000 Bergen Ed 1962 M 7000 Mons Project-Join-Repair (Ex.  ...  Project-Join-Repair Σ = set of fd's σ = join dependency (jd) I = possibly inconsistent relation We repair σ(I)-rather than I. Note that σ(I) ⊇ I. We require Σ |= σ.  ...  Conclusion Database repairing and consistent query answering under fd's.  ... 
doi:10.1007/11766254_1 fatcat:fkwkaa2smvfyfmgorq6m2bvzbi

Certain query answering in partially consistent databases

Sergio Greco, Fabian Pijcke, Jef Wijsen
2014 Proceedings of the VLDB Endowment  
We focus on the complexity of CERTAINTY(q, Σ) when q is an acyclic conjunctive query without self-join, and Σ is a set of functional dependencies and join dependencies, the latter of a particular form.  ...  In practice, however, it may be known that these input databases are partially consistent, in the sense that they satisfy some dependencies (e.g., functional dependencies).  ...  To answer queries on uncertain databases, we follow the paradigm of consistent query answering [3, 5] , which we also refer to as certain query answering.  ... 
doi:10.14778/2732269.2732272 fatcat:2piby4ln65hgpdmkeh5ycujf4y