Incomplete Information in Relational Databases
Journal of the ACM (JACM)
On the representation and querying of sets of possible worlds
Selected papers of the workshop on Deductive database theory
Incomplete object—a data model for design and planning applications
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Converting nested algebra expressions into flat algebra expressions
ACM Transactions on Database Systems (TODS)
Semantic representations and query languages for or-sets
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
A framework for implementing hypothetical queries
SIGMOD '97 Proceedings of the 1997 ACM SIGMOD international conference on Management of data
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
New TPC benchmarks for decision support and web commerce
ACM SIGMOD Record
Problem of Incomplete Information in Relational Databases
Problem of Incomplete Information in Relational Databases
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Dependency Satisfaction in Databases with Incomplete Information
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
Answer sets for consistent query answering in inconsistent databases
Theory and Practice of Logic Programming
The INFOMIX system for advanced integration of incomplete and inconsistent data
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Laws for Rewriting Queries Containing Division Operators
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
Clean Answers over Dirty Databases: A Probabilistic Approach
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
ULDBs: databases with uncertainty and lineage
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Efficient query evaluation on probabilistic databases
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
World-set decompositions: expressiveness and efficient algorithms
ICDT'07 Proceedings of the 11th international conference on Database Theory
Models for incomplete and probabilistic information
EDBT'06 Proceedings of the 2006 international conference on Current Trends in Database Technology
Query language support for incomplete information in the MayBMS system
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
Finding frequent items in probabilistic data
Proceedings of the 2008 ACM SIGMOD international conference on Management of data
Approximating predicates and expressive queries on probabilistic databases
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Dependencies revisited for improving data quality
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
World-set decompositions: Expressiveness and efficient algorithms
Theoretical Computer Science
Generating efficient safe query plans for probabilistic databases
Data & Knowledge Engineering
A compositional query algebra for second-order logic and uncertain databases
Proceedings of the 12th International Conference on Database Theory
Containment of conjunctive queries on annotated relations
Proceedings of the 12th International Conference on Database Theory
On Query Algebras for Probabilistic Databases
ACM SIGMOD Record
Consensus answers for queries over probabilistic databases
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Ranking distributed probabilistic data
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Indexing correlated probabilistic databases
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
The VLDB Journal — The International Journal on Very Large Data Bases
Believe it or not: adding belief annotations to databases
Proceedings of the VLDB Endowment
Probabilistic ranking over relations
Proceedings of the 13th International Conference on Extending Database Technology
On probabilistic fixpoint and Markov chain query languages
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the optimal approximation of queries using tractable propositional languages
Proceedings of the 14th International Conference on Database Theory
Robust ranking of uncertain data
DASFAA'11 Proceedings of the 16th international conference on Database systems for advanced applications - Volume Part I
Handling ER-topk query on uncertain streams
DASFAA'11 Proceedings of the 16th international conference on Database systems for advanced applications - Volume Part I
Tiresias: the database oracle for how-to queries
SIGMOD '12 Proceedings of the 2012 ACM SIGMOD International Conference on Management of Data
Tiresias: a demonstration of how-to queries
SIGMOD '12 Proceedings of the 2012 ACM SIGMOD International Conference on Management of Data
Xtream: a system for continuous querying over uncertain data streams
SUM'12 Proceedings of the 6th international conference on Scalable Uncertainty Management
Efficient recovery of missing events
Proceedings of the VLDB Endowment
Top-k entities query processing on uncertainly fused multi-sensory data
Personal and Ubiquitous Computing
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Incomplete information arises naturally in numerous data management applications. Recently, several researchers have studied query processing in the context of incomplete information. Most work has combined the syntax of a traditional query language like relational algebra with a nonstandard semantics such as certain or ranked possible answers. There are now also languages with special features to deal with uncertainty. However, to the standards of the data management community, to date no language proposal has been made that can be considered a natural analog to SQL or relational algebra for the case of incomplete information. In this paper we propose such a language, World-set Algebra, which satisfies the robustness criteria and analogies to relational algebra that we expect. The language supports the contemplation on alternatives and can thus map from a complete database to an incomplete one comprising several possible worlds. We show that World-set Algebra is conservative over relational algebra in the sense that any query that maps from a complete database to a complete database (a complete-to-complete query) is equivalent to a relational algebra query. Moreover, we give an efficient algorithm for effecting this translation. We then study algebraic query optimization of such queries. We argue that query languages with explicit constructs for handling uncertainty allow for the more natural and simple expression of many real-world decision support queries. The results of this paper not only suggest a language for specifying queries in this way, but also allow for their efficient evaluation in any relational database management system.