Notions of dependency satisfaction
Journal of the ACM (JACM) - The MIT Press scientific computation series
Partition semantics for relations
Journal of Computer and System Sciences
Functional dependencies and constraints on Null values in database relations
Information and Control
Database states and their tableaux
ACM Transactions on Database Systems (TODS)
On the foundations of the universal relation model
ACM Transactions on Database Systems (TODS)
A characterization of globally consistent databases and their correct access paths
ACM Transactions on Database Systems (TODS)
Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
On the Equivalence of Database Models
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)
On computing restricted projections of representative instances
PODS '85 Proceedings of the fourth ACM SIGACT-SIGMOD symposium on Principles of database systems
Efficient query answering in the representative instance approach
PODS '85 Proceedings of the fourth ACM SIGACT-SIGMOD symposium on Principles of database systems
Can we use the universal instance assumption without using nulls?
SIGMOD '81 Proceedings of the 1981 ACM SIGMOD international conference on Management of data
Optimal computation of total projections with unions of simple chase join expressions
SIGMOD '84 Proceedings of the 1984 ACM SIGMOD international conference on Management of data
Query answering and schema analysis under the weak instance model
Query answering and schema analysis under the weak instance model
Updating databases in the weak instance model
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Efficient updates to independent schemes in the weak instance model
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Independence-reducible database schemes
Journal of the ACM (JACM)
Updating relational databases through weak instance interfaces
ACM Transactions on Database Systems (TODS)
Semantics for null extended nested relations
ACM Transactions on Database Systems (TODS)
Independent Database Schemes under Functional and Inclusion Dependencies
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
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A new definition of the weak instance model is presented, which does not consider the missing values as existent though unknown, but just assumes that no information is available about them. It is possible to associate with the new definition logical theories that do not contain universally quantified variables. The new model enjoys various desirable properties of the old weak instance model, with respect to dependency satisfaction, query answering, and associated logical theories.