Distributed databases principles and systems
Distributed databases principles and systems
Optimizing chain queries in a distributed database system.
SIAM Journal on Computing
Query Processing in a Fragmented Relational Distributed System: Mermaid
IEEE Transactions on Software Engineering - Annals of discrete mathematics, 24
An Optimal Algorithm for Processing Distributed Star Queries
IEEE Transactions on Software Engineering
Query optimization by semantic reasoning
Query optimization by semantic reasoning
Multibase—integrating heterogeneous distributed database systems
AFIPS Conference Proceedings; vol. 55 1986 National Computer Conference
Data Integration in Distributed Databases
IEEE Transactions on Software Engineering
A system for semantic query optimization
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Integrating relational databases with support for updates
DPDS '88 Proceedings of the first international symposium on Databases in parallel and distributed systems
Partition Strategy for Distributed Query Processing in Fast Local Networks
IEEE Transactions on Software Engineering
A localized approach to distributed query processing
EDBT '90 Proceedings of the 2nd international conference on extending database technology: Advances in Database Technology
Query processing in a system for distributed databases (SDD-1)
ACM Transactions on Database Systems (TODS)
Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
Database abstractions: aggregation and generalization
ACM Transactions on Database Systems (TODS)
Using Semi-Joins to Solve Relational Queries
Journal of the ACM (JACM)
Implementation of integrity constraints and views by query modification
SIGMOD '75 Proceedings of the 1975 ACM SIGMOD international conference on Management of data
On the design of a query processing strategy in a distributed database environment
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
Using semiouterjoins to process queries in multidatabase systems
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
An Approach to Schema Integration and Query Formulation in Federated Database Systems
Proceedings of the Third International Conference on Data Engineering
Queries in Object-Oriented Databases
Proceedings of the Fourth International Conference on Data Engineering
Adaptive Techniques for Distributed Query Optimization
Proceedings of the Second International Conference on Data Engineering
Database Integration in a Distributed Heterogeneous Database System
Proceedings of the Second International Conference on Data Engineering
Optimizing Star Queries in a Distributed Database System
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
On global multidatabase query optimization
ACM SIGMOD Record
Progress in Database Search Strategies
IEEE Software
Database research at NTHU and ITRI
ACM SIGMOD Record
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Reducing multidatabase query response time by tree balancing
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
Hypergraph based reorderings of outer join queries with complex predicates
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
Outerjoin simplification and reordering for query optimization
ACM Transactions on Database Systems (TODS)
Query Optimization in Multidatabase Systems Considering Schema Conflicts
IEEE Transactions on Knowledge and Data Engineering
Efficient Query Processing in Integrated Multiple Object Databases with Maybe Result Certification
IEEE Transactions on Knowledge and Data Engineering
Semantic Conflicts and Solutions in Fuzzy Multidatabase Systems
DNIS '00 Proceedings of the International Workshop on Databases in Networked Information Systems
Entity identification of fuzzy multidatabase systems with incompatible keys
Web-enabled systems integration
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
CASCON '95 Proceedings of the 1995 conference of the Centre for Advanced Studies on Collaborative research
Distributed and Parallel Databases
Efficient outer join data skew handling in parallel DBMS
Proceedings of the VLDB Endowment
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Outerjoin is used in distributed relational multidatabase systems for integrating local schemas to a global schema. Queries against the global schema need to be modified, optimized, and decomposed into subqueries at local sites for processing. Since outerjoin combines local relations in different databases to form a global relation, it is expensive to process. In this paper, based on the structure of the query and the definition of the schemas, queries with outerjoin, join, select and project operations are optimized. Conditions where outerjoin can be avoided or be transformed into a one-side outerjoin are identified. By considering these conditions the response time for query processing can be reduced.