PIQUE: A relational query language without relations
Information Systems
Data caching issues in an information retrieval system
ACM Transactions on Database Systems (TODS)
Safety and translation of relational calculus
ACM Transactions on Database Systems (TODS)
Using powerdomains to generalize relational databases
Theoretical Computer Science
Domain independence and the relational calculus
Acta Informatica
The Recursive Unsolvability of the Decision Problem for the Class of Definite Formulas
Journal of the ACM (JACM)
Horn clauses and database dependencies
Journal of the ACM (JACM)
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
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This paper describes a method for answering all relational calculus queries under the assumption that the domain of data values is sufficiently large. The method extends recent theoretical results that use extended relation representations to answer domain dependent queries, without the use of auxilliary variables or invented constants or an explicit enumeration of the active domain. The method is shown to be logically correct and to have polynomial data complexity. By identifying relational algebra operations with relational calculus queries this approach extends relational algebra to a full boolean algebra, where intersection, union, and difference are defined between any two relations, whether or not they are union compatible. An example illustrates that this approach can be useful in distributed query optimization.