Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Complexity of query processing in databases with OR-objects
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
A semantics for reasoning consistently in the presence of inconsistency
Artificial Intelligence
Null inclusion dependencies in relational databases
Information and Computation
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On semantic issues connected with incomplete information databases
ACM Transactions on Database Systems (TODS)
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Database relations with null values
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Reasoning in Inconsistent Knowledge Bases
IEEE Transactions on Knowledge and Data Engineering
Flexible Relation: An Approach for Integrating Data from Multiple, Possibly Inconsistent Databases
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
A Logic Programming Approach to the Integration, Repairing and Querying of Inconsistent Databases
Proceedings of the 17th International Conference on Logic Programming
Data Integration under Integrity Constraints
CAiSE '02 Proceedings of the 14th International Conference on Advanced Information Systems Engineering
Query Answering in Information Systems with Integrity Constraints
Proceedings of the IFIP TC11 Working Group 11.5, First Working Conference on Integrity and Internal Control in Information Systems: Increasing the confidence in Information Systems
Integrating data from possibly inconsistent databases
COOPIS '96 Proceedings of the First IFCIS International Conference on Cooperative Information Systems
A Logical Framework for Querying and Repairing Inconsistent Databases
IEEE Transactions on Knowledge and Data Engineering
Database repairing using updates
ACM Transactions on Database Systems (TODS)
Consistent query answering in databases
ACM SIGMOD Record
Minimal-change integrity maintenance using tuple deletions
Information and Computation
Querying inconsistent databases
LPAR'00 Proceedings of the 7th international conference on Logic for programming and automated reasoning
Consistent query answering: five easy pieces
ICDT'07 Proceedings of the 11th international conference on Database Theory
Semantically correct query answers in the presence of null values
EDBT'06 Proceedings of the 2006 international conference on Current Trends in Database Technology
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This paper investigates the problem of repairing and querying relational databases which may be inconsistent with respect to functional dependencies and foreign key constraints. Specifically, particular sets of functional dependencies, called canonical, are considered. We present a repairing strategy whereby only tuple updates and insertions are allowed in order to restore consistency: when foreign key constraints are violated, new tuples (possibly containing null values) are inserted into the database; when functional dependency violations occur, tuple updates (possibly introducing unknown values) are performed. We propose a semantics of constraint satisfaction for databases containing null and unknown values, since the repairing process can lead to such databases. The proposed approach allows us to obtain a unique repaired database which can be computed in polynomial time. The result of the repairing technique is an incomplete database (in particular, an OR-database). The consistentquery answers over an inconsistent database are the certainanswers on the repaired database. Relying on the results in [17] on the complexity of query processing in OR-databases, we can identify conjunctive queries which can be evaluated in polynomial time.