Integrity = validity + completeness
ACM Transactions on Database Systems (TODS)
Obtaining Complete Answers from Incomplete Databases
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Multi-paradigm Java-Prolog integration in tuProlog
Science of Computer Programming
The DLV system for knowledge representation and reasoning
ACM Transactions on Computational Logic (TOCL)
Relative information completeness
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Capturing missing tuples and missing values
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
MAGIK: managing completeness of data
Proceedings of the 21st ACM international conference on Information and knowledge management
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We present a system that computes for a query that may be incomplete, complete approximations from above and from below. We assume a setting where queries are posed over a partially complete database, that is, a database that is generally incomplete, but is known to contain complete information about specific aspects of its application domain. Which parts are complete, is described by a set of so-called table-completeness statements. Previous work led to a theoretical framework and an implementation that allowed one to determine whether in such a scenario a given conjunctive query is guaranteed to return a complete set of answers or not. With the present demonstrator we show how to reformulate the original query in such a way that answers are guaranteed to be complete. If there exists a more general complete query, there is a unique most specific one, which we find. If there exists a more specific complete query, there may even be infinitely many. In this case, we find the least specific specializations whose size is bounded by a threshold provided by the user. Generalizations are computed by a fixpoint iteration, employing an answer set programming engine. Specializations are found leveraging unification from logic programming.