Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Logic-based approach to semantic query optimization
ACM Transactions on Database Systems (TODS)
Clique partitions, graph compression and speeding-up algorithms
STOC '91 Proceedings of the twenty-third annual ACM symposium on Theory of computing
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
On the Multiple-Query Optimization Problem
IEEE Transactions on Knowledge and Data Engineering
Security Constraint Processing in a Multilevel Secure Distributed Database Management System
IEEE Transactions on Knowledge and Data Engineering
Overview of Dynamic Query Evaluationin Intensional Query Optimization
DOOD '97 Proceedings of the 5th International Conference on Deductive and Object-Oriented Databases
Semantic Query Reformulation in Deductive Databases
Proceedings of the Seventh International Conference on Data Engineering
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
Semantic Data Caching and Replacement
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Semantic Query Optimization for Bottom-Up Evaluation
ISMIS '96 Proceedings of the 9th International Symposium on Foundations of Intelligent Systems
An architecture and implementation for a cooperative database system
An architecture and implementation for a cooperative database system
Answering Queries by Semantic Caches
DEXA '99 Proceedings of the 10th International Conference on Database and Expert Systems Applications
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We explore a new form of view rewrite called view disassembly. The objective is to rewrite views in order to "remove" certain sub-views (or unfoldings) of the view. This becomes pertinent for complex views which may defined over other views and which may involve union. Such complex views arise necessarily in environments as data warehousing and mediation over heterogeneous databases. View disassembly can be used for view and query optimization, preserving data security, making use of cached queries and materialized views, and view maintenance. We provide computational complexity results of view disassembly. We show that the optimal rewrites for disassembled views is at least NP-hard. However, we provide good news too. We provide an approximation algorithm that has much better run-time behavior. We show a pertinent class of unfoldings for which their removal always results in a simpler disassembled view than the view itself. We also show the complexity to determine when a collection of unfoldings cover the view definition.