The design and analysis of algorithms
The design and analysis of algorithms
PP is as hard as the polynomial-time hierarchy
SIAM Journal on Computing
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the Structure of Polynomial Time Reducibility
Journal of the ACM (JACM)
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Scalar aggregation in inconsistent databases
Theoretical Computer Science - Database theory
Clean Answers over Dirty Databases: A Probabilistic Approach
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
First-order query rewriting for inconsistent databases
Journal of Computer and System Sciences
Management of probabilistic data: foundations and challenges
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The dichotomy of conjunctive queries on probabilistic structures
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Approximate Probabilistic Query Answering over Inconsistent Databases
ER '08 Proceedings of the 27th International Conference on Conceptual Modeling
Probabilistic databases: diamonds in the dirt
Communications of the ACM - Barbara Liskov: ACM's A.M. Turing Award Winner
MayBMS: a probabilistic database management system
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
On the consistent rewriting of conjunctive queries under primary key constraints
Information Systems
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)
Certain conjunctive query answering in SQL
SUM'12 Proceedings of the 6th international conference on Scalable Uncertainty Management
Charting the tractability frontier of certain conjunctive query answering
Proceedings of the 32nd symposium on Principles of database systems
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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 is obtained by selecting a maximal number of tuples without ever selecting two distinct tuples of the same relation that agree on their primary key. Obviously, the number of possible repairs can be exponential in the size of the database. Given a Boolean query q, certain (or consistent) query answering concerns the problem to decide whether q evaluates to true on every repair. In this article, we study a counting variant of consistent query answering. For a fixed Boolean query q, we define @?CERTAINTY(q) as the following counting problem: Given an uncertain database db, how many repairs of db satisfy q? Our main result is that conjunctive queries q without self-join exhibit a complexity dichotomy: @?CERTAINTY(q) is in FP or @?P-complete.