Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
Using Semi-Joins to Solve Relational Queries
Journal of the ACM (JACM)
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Properties of acyclic database schemes
STOC '81 Proceedings of the thirteenth annual ACM symposium on Theory of computing
ACM Computing Surveys (CSUR)
Elimination of intersection anomalies from database schemes
Journal of the ACM (JACM)
A theory of intersection anomalies in relational database schemes
Journal of the ACM (JACM)
Graph-theoretic methods in database theory
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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
Query processing utilizing dependencies and horizontal decomposition
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
On the recognition and design of acyclic databases
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
On the cyclic to acyclic scheme transformation and solving cyclic queries
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
GYO reductions, canonical connections, tree and cyclic schemas and tree projections
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Elimination of intersection amomalies from database schemes
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
SIGMOD '84 Proceedings of the 1984 ACM SIGMOD international conference on Management of data
A Graph Theoretical Approach to Determine a Join Reducer Sequence in Distributed Query Processing
IEEE Transactions on Knowledge and Data Engineering
On the Complexity of Distributed Query Optimization
IEEE Transactions on Knowledge and Data Engineering
Interleaving a Join Sequence with Semijoins in Distributed Query Processing
IEEE Transactions on Parallel and Distributed Systems
Combining Joint and Semi-Join Operations for Distributed Query Processing
IEEE Transactions on Knowledge and Data Engineering
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One can partition the class of relational database schemas into tree schemas and cyclic schemas. In this paper we examine query processing implications of the partitioning; other areas impacted include dependency theory, schema design and graph theory.We consider a class of queries that compute the join of all relations in the database projected onto a prescribed set of attributes. We show that solving such queries (using the join, project and semijoin operators) is tantamount to creating an "embedded" tree schema which we call a tree projection. This lends further credibility to the pivotal nature of the tree/cyclic partitioning.Using the tree projection concept we analyze the problem of determining how many joins are needed to solve a query.