Variations on the Common Subexpression Problem
Journal of the ACM (JACM)
On the Complexity of Testing Implications of Functional and Join Dependencies
Journal of the ACM (JACM)
Testing satisfaction of functional dependencies
Journal of the ACM (JACM)
Horn clauses and database dependencies
Journal of the ACM (JACM)
A relational model of data for large shared data banks
Communications of the ACM
Programming primitives for database languages
POPL '81 Proceedings of the 8th ACM SIGPLAN-SIGACT symposium on Principles of programming languages
Universality of data retrieval languages
POPL '79 Proceedings of the 6th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
Can we use the universal instance assumption without using nulls?
SIGMOD '81 Proceedings of the 1981 ACM SIGMOD international conference on Management of data
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Relational queries computable in polynomial time (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Notions of dependency satisfaction
Journal of the ACM (JACM) - The MIT Press scientific computation series
On the integrity of databases with incomplete information
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Parallel evaluation of recursive rule queries
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Constant-time maintainability: a generalization of independence
ACM Transactions on Database Systems (TODS)
On the foundations of the universal relation model
ACM Transactions on Database Systems (TODS)
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A database is consistent with respect to a set σ of dependencies if it has a weak instance. A weak instance is a universal relation that satisfies Σ, and whose projections on the relation schemes are supersets of the relations in the database. In this paper we investigate the complexity of testing consistency and the logics that can axiomatize consistency, relative to a fixed set Σ of dependencies. If Σ is allowed to include embedded dependencies, then consistency can be non-recursive. If Σ consists only of total dependencies, then consistency can be tested in polynomial time. The degree of the polynomial can, however, be arbitrarily high. Consistency can be axiomatized but not finitely axiomatized by equality generating dependencies. If embedded dependencies are allowed then consistency cannot be finitely axiomatized by any effective logic. If, on the other hand, only total dependencies are allowed then consistency can be finitely axiomatized by fixpoint logic.