Relative information capacity of simple relational database schemata
SIAM Journal on Computing
Restructuring hierarchical database objects
Theoretical Computer Science - First International Conference on Database Theory, Rome, September 1986
Equivalence of datalog queries is undecidable
Journal of Logic Programming
Schema equivalence in heterogeneous systems: bridging theory and practice
Information Systems - Special issue on extending database technology
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Conjunctive Query Containment Revisited
ICDT '97 Proceedings of the 6th International Conference on Database Theory
The Use of Information Capacity in Schema Integration and Translation
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Views and queries: determinacy and rewriting
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Designing information-preserving mapping schemes for XML
VLDB '05 Proceedings of the 31st international conference on Very large data bases
View-based query processing: On the relationship between rewriting, answering and losslessness
Theoretical Computer Science
Queries determined by views: pack your views
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Information preserving XML schema embedding
ACM Transactions on Database Systems (TODS)
Views and queries: Determinacy and rewriting
ACM Transactions on Database Systems (TODS)
Determinacy and query rewriting for conjunctive queries and views
Theoretical Computer Science
Conjunctive queries determinacy and rewriting
Proceedings of the 14th International Conference on Database Theory
Determinacy and rewriting of conjunctive queries over unary database schemas
Proceedings of the 2011 ACM Symposium on Applied Computing
Determinacy and rewriting of conjunctive queries using views: a progress report
ICDT'07 Proceedings of the 11th international conference on Database Theory
On the Complexity of View Update Analysis and Its Application to Annotation Propagation
IEEE Transactions on Knowledge and Data Engineering
Exact query reformulation with first-order ontologies and databases
JELIA'12 Proceedings of the 13th European conference on Logics in Artificial Intelligence
Exact query reformulation over databases with first-order and description logics ontologies
Journal of Artificial Intelligence Research
Quality of information-based source assessment and selection
Neurocomputing
Hi-index | 0.00 |
When transforming data one often wants certain information in the data source to be preserved, i.e.,we identify parts of the source data and require these parts to be transformed without loss of information. We characterize the preservation of selected information in terms of the notions of invertibility and query preservation, in a setting when transformations are specified as a view V (a set of queries), and source information is selected by a query Q. We investigate the problem for determining whether transformations V preserve the information selected by Q. (1) We show that the notion of invertibility coincides with view determinacy studied for query rewriting. (2) We establish the undecidability of the problem when either Q or V is in DATALOG or first-order logic, for invertibility and query preservation. (3) When Q and V are conjunctive queries (CQ), the problem is as hard as view determinacy for CQ queries and CQ views, an open problem. Nevertheless, we provide complexity bounds of the problem, either in ptime or np-complete, when V ranges over subclasses of CQ (i.e.,SP, SC, PC), and when Q is assumed to be a minimal CQ query or not. (4) We show that CQ is complete for L-to-CQ rewriting when L is SP, SC or PC, i.e.,every CQ query can be rewritten in terms of SP, SC or PC views using a query in CQ.