A simplied universal relation assumption and its properties
ACM Transactions on Database Systems (TODS)
Maximal objects and the semantics of universal relation databases
ACM Transactions on Database Systems (TODS)
A characterization of globally consistent databases and their correct access paths
ACM Transactions on Database Systems (TODS)
The theory of joins in relational databases
ACM Transactions on Database Systems (TODS)
Efficient optimization of a class of relational expressions
ACM Transactions on Database Systems (TODS)
Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
Equivalences Among Relational Expressions with the Union and Difference Operators
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
A generalized access path model and its application to a relational data base system
SIGMOD '76 Proceedings of the 1976 ACM SIGMOD international conference on Management of data
An algorithm for servicing multi-relational queries
SIGMOD '77 Proceedings of the 1977 ACM SIGMOD international conference on Management of data
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
Can we use the universal instance assumption without using nulls?
SIGMOD '81 Proceedings of the 1981 ACM SIGMOD international conference on Management of data
Specifying connections for a universal relation scheme database
SIGMOD '82 Proceedings of the 1982 ACM SIGMOD international conference on Management of data
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Independent and separable database schemes
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
The Implication Problem for Data Dependencies
Proceedings of the 8th Colloquium on Automata, Languages and Programming
Query answering and schema analysis under the weak instance model
Query answering and schema analysis under the weak instance model
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
A new basis for the weak instance model
PODS '87 Proceedings of the sixth 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
Constant-time-maintainable BCNF database schemes
ACM Transactions on Database Systems (TODS)
Independence-reducible database schemes
Journal of the ACM (JACM)
Updating relational databases through weak instance interfaces
ACM Transactions on Database Systems (TODS)
Independence-reducible database schemes
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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The representative instance has been proposed as a query answering device in systems using the Universal Relation Interface. One approach is to use the total projections of the representative instance to generate the answer for a query. Associated with this approach is the problem of how to generate the total projections of the representative instance efficiently. We propose a generalization of extension joins, called chase join expressions, as a means to compute the total projections when functional dependencies are given as constraints. In particular, we identify an important subclass of chase join expressions called simple chase join expressions and show that the total projections with respect to a set of functional dependencies can be computed by unions of simple chase join expressions when an independent scheme is assumed. We also find a simple and efficient algorithm that minimizes the number of join operations in a union of simple chase join expressions.