Decomposition—a strategy for query processing
ACM Transactions on Database Systems (TODS)
Multivalued dependencies and a new normal form for relational databases
ACM Transactions on Database Systems (TODS)
Independent components of relations
ACM Transactions on Database Systems (TODS)
Optimizing the performance of a relational algebra database interface
Communications of the ACM
A relational model of data for large shared data banks
Communications of the ACM
Performing inferences over relation data bases
SIGMOD '75 Proceedings of the 1975 ACM SIGMOD international conference on Management of data
Efficient optimization of a class of relational expressions
SIGMOD '78 Proceedings of the 1978 ACM SIGMOD international conference on management of data
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
The Design and Analysis of Computer Algorithms
The Design and Analysis of Computer Algorithms
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
The complexity of theorem-proving procedures
STOC '71 Proceedings of the third annual ACM symposium on Theory of computing
Verification of query completeness over processes
BPM'13 Proceedings of the 11th international conference on Business Process Management
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A generalization of tableaux as a method for representing queries in relational databases, called sets of tableaux, is proposed. Every relational expression with the operators select, project, join and union can be represented by a set of tableaux. This paper studies the equivalence problem for sets of tableaux. It is shown that the theory of tableaux is easily extended to sets of tableaux, but the equivalence problem for sets of tableaux (as well as the containment problem for single tableaux) is NP-complete even in very restricted cases. Polynomial time algorithms for testing equivalence of sets of tableaux (and containment of tableaux) in three special cases are presented. Sets of tableaux are further generalized to sets of elementary differences in order to include also the difference operator. The equivalence problem for sets of elementary differences is investigated.