Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Optimization of real conjunctive queries
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Containment of conjunctive queries: beyond relations as sets
ACM Transactions on Database Systems (TODS)
A probabilistic relational algebra for the integration of information retrieval and database systems
ACM Transactions on Information Systems (TOIS)
Query evaluation in probabilistic relational databases
Selected papers from the international workshop on Uncertainty in databases and deductive systems
Equivalences Among Relational Expressions with the Union and Difference Operators
Journal of the ACM (JACM)
Tracing the lineage of view data in a warehousing environment
ACM Transactions on Database Systems (TODS)
Semantics and Containment with Internal and External Conjunctions
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Why and Where: A Characterization of Data Provenance
ICDT '01 Proceedings of the 8th International Conference on Database Theory
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
The containment problem for Real conjunctive queries with inequalities
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Deciding equivalences among conjunctive aggregate queries
Journal of the ACM (JACM)
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Quasi-inverses of schema mappings
ACM Transactions on Database Systems (TODS)
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Exploiting Lineage for Confidence Computation in Uncertain and Probabilistic Databases
ICDE '08 Proceedings of the 2008 IEEE 24th International Conference on Data Engineering
Query containment under bag and bag-set semantics
Information Processing Letters
Containment of Conjunctive Queries on Annotated Relations
Theory of Computing Systems
A general framework for representing, reasoning and querying with annotated Semantic Web data
Web Semantics: Science, Services and Agents on the World Wide Web
Equivalence and minimization of conjunctive queries under combined semantics
Proceedings of the 15th International Conference on Database Theory
Factorised representations of query results: size bounds and readability
Proceedings of the 15th International Conference on Database Theory
Semiring-annotated data: queries and provenance?
ACM SIGMOD Record
Classification of annotation semirings over containment of conjunctive queries
ACM Transactions on Database Systems (TODS)
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We study the problem of query containment of (unions of) conjunctive queries over annotated databases. Annotations are typically attached to tuples and represent metadata such as probability, multiplicity, comments, or provenance. It is usually assumed that annotations are drawn from a commutative semiring. Such databases pose new challenges in query optimization, since many related fundamental tasks, such as query containment, have to be reconsidered in the presence of propagation of annotations. We axiomatize several classes of semirings for each of which containment of conjunctive queries is equivalent to existence of a particular type of homomorphism. For each of these types we also specify all semirings for which existence of a corresponding homomorphism is a sufficient (or necessary) condition for the containment. We exploit these techniques to develop new decision procedures for containment of unions of conjunctive queries and axiomatize corresponding classes of semirings. This generalizes previous approaches and allows us to improve known complexity bounds.