Incomplete Information in Relational Databases
Journal of the ACM (JACM)
On the integrity of databases with incomplete information
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Integrity = validity + completeness
ACM Transactions on Database Systems (TODS)
On the representation and querying of sets of possible worlds
Selected papers of the workshop on Deductive database theory
Generalizations of Opt P to the polynomial hierarchy
Theoretical Computer Science
Equivalence, query-reachability and satisfiability in Datalog extensions
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Complexity of answering queries using materialized views
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Logical approaches to incomplete information: a survey
Logics for databases and information systems
Independence of logic database queries and update
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Problem of Incomplete Information in Relational Databases
Problem of Incomplete Information in Relational Databases
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
On XML integrity constraints in the presence of DTDs
Journal of the ACM (JACM)
Closed World Databases Opened Through Null Values
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
Queries Independent of Updates
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Obtaining Complete Answers from Incomplete Databases
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Views and queries: determinacy and rewriting
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Schema mappings, data exchange, and metadata management
Proceedings of the twenty-fourth 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
Master Data Management
Relative information completeness
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Static analysis of schema-mappings ensuring oblivious termination
Proceedings of the 13th International Conference on Database Theory
Composition and inversion of schema mappings
ACM SIGMOD Record
Consistent query answering: five easy pieces
ICDT'07 Proceedings of the 11th international conference on Database Theory
Relative information completeness
ACM Transactions on Database Systems (TODS)
Checking query completeness over incomplete data
Proceedings of the 4th International Workshop on Logic in Databases
Incomplete databases: missing records and missing values
DASFAA'12 Proceedings of the 17th international conference on Database Systems for Advanced Applications
Completeness of queries over SQL databases
Proceedings of the 21st ACM international conference on Information and knowledge management
MAGIK: managing completeness of data
Proceedings of the 21st ACM international conference on Information and knowledge management
Towards unified and native enrichment in event processing systems
Proceedings of the 7th ACM international conference on Distributed event-based systems
Complete approximations of incomplete queries
Proceedings of the VLDB Endowment
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Databases in real life are often neither entirely closed-world nor entirely open-world. Indeed, databases in an enterprise are typically partially closed, in which a part of the data is constrained by master data that contains complete information about the enterprise in certain aspects [21]. It has been shown that despite missing tuples, such a database may turn out to have complete information for answering a query [9]. This paper studies partially closed databases from which both tuples and values may be missing. We specify such a database in terms of conditional tables constrained by master data, referred to as c-instances. We first propose three models to characterize whether a c-instance T is complete for a query Q relative to master data. That is, depending on how missing values in T are instantiated, the answer to Q in T remains unchanged when new tuples are added. We then investigate four problems, to determine (a) whether a given c-instance is complete for a query Q, (b) whether there exists a c-instance that is complete for Q relative to master data available, (c) whether a c-instance is a minimal-size database that is complete for Q, and (d) whether there exists a c-instance of a bounded size that is complete for Q. We establish matching lower and upper bounds on these problems for queries expressed in a variety of languages, in each of the three models for specifying relative completeness.