Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the Desirability of Acyclic Database Schemes
Journal of the ACM (JACM)
Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
ConQuer: efficient management of inconsistent databases
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
First-order query rewriting for inconsistent databases
Journal of Computer and System Sciences
Probabilistic databases: diamonds in the dirt
Communications of the ACM - Barbara Liskov: ACM's A.M. Turing Award Winner
On the consistent rewriting of conjunctive queries under primary key constraints
Information Systems
Minimal-change integrity maintenance using tuple deletions
Information and Computation
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
A remark on the complexity of consistent conjunctive query answering under primary key violations
Information Processing Letters
Queries and materialized views on probabilistic databases
Journal of Computer and System Sciences
Proceedings of the 4th International Workshop on Logic in Databases
A dichotomy in the complexity of consistent query answering for queries with two atoms
Information Processing Letters
Certain conjunctive query answering in first-order logic
ACM Transactions on Database Systems (TODS)
Database Repairing and Consistent Query Answering
Database Repairing and Consistent Query Answering
A dichotomy in the complexity of counting database repairs
Journal of Computer and System Sciences
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An uncertain database db is defined as a database in which distinct tuples of the same relation can agree on their primary key. A repair (or possible world) of db is then obtained by selecting a maximal number of tuples without ever selecting two distinct tuples of the same relation that agree on their primary key. Given a query Q on db, the certain answer is the intersection of the answers to Q on all repairs. Recently, a syntactic characterization was obtained of the class of acyclic self-join-free conjunctive queries for which certain answers are definable by a first-order formula, called certain first-order rewriting [15]. In this article, we investigate the nesting and alternation of quantifiers in certain first-order rewritings, and propose two syntactic simplification techniques. We then experimentally verify whether these syntactic simplifications result in lower execution times on real-life SQL databases.