An extension of conflict-free multivalued dependency sets
ACM Transactions on Database Systems (TODS)
GYO reductions, canonical connections, tree and cyclic schemas, and tree projections
Journal of Computer and System Sciences
The equivalence of solving queries and producing tree projections (extended abstract)
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
A simplied universal relation assumption and its properties
ACM Transactions on Database Systems (TODS)
Tree queries: a simple class of relational queries
ACM Transactions on Database Systems (TODS)
Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
Using Semi-Joins to Solve Relational Queries
Journal of the ACM (JACM)
On the Desirability of Acyclic Database Schemes
Journal of the ACM (JACM)
Degrees of acyclicity for hypergraphs and relational database schemes
Journal of the ACM (JACM)
Syntactic Characterization of Tree Database Schemas
Journal of the ACM (JACM)
The Design and Analysis of Computer Algorithms
The Design and Analysis of Computer Algorithms
Query processing utilizing dependencies and horizontal decomposition
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
Functional dependencies on cyclic database schemes
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
Query processing for distributed databases using generalized semi-joins
SIGMOD '82 Proceedings of the 1982 ACM SIGMOD international conference on Management of data
Properties of database schemata with functional dependencies
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
Transforming cyclic schemas into trees
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Properties of acyclic database schemes
STOC '81 Proceedings of the thirteenth annual ACM symposium on Theory of computing
Graphs and Hypergraphs
Avoiding Cartesian products for multiple joins
Journal of the ACM (JACM)
The complexity of acyclic conjunctive queries
Journal of the ACM (JACM)
Generalized hypertree decompositions: np-hardness and tractable variants
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Generalized hypertree decompositions: NP-hardness and tractable variants
Journal of the ACM (JACM)
Tree Projections: Game Characterization and Computational Aspects
Graph Theory, Computational Intelligence and Thought
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Structural tractability of enumerating CSP solutions
CP'10 Proceedings of the 16th international conference on Principles and practice of constraint programming
Theoretical Computer Science
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Suppose a database schema D is extended to D¯ by adding new relation schemas, and states for D are extended to states for D¯ by applying joins and projections to existing relations. It is shown that certain desirable properties that D¯ has with respect to D. These properties amount to the ability to compute efficiently the join of all relations in a state for D from an extension of this state over D¯. The equivalence is proved for unrestricted (i.e., both finite and infinite) databases. If D¯ is obtained from D by adding a set of new relation schemas that form a tree schema, then the equivalence also holds for finite databases. In this case there is also a polynomial time algorithm for testing the existence of a tree projection of D¯ with respect to D.