Hierarchical schemata for relational databases
ACM Transactions on Database Systems (TODS)
Consequences of assuming a universal relation
ACM Transactions on Database Systems (TODS)
On semantic issues connected with incomplete information databases
ACM Transactions on Database Systems (TODS)
The theory of joins in relational databases
ACM Transactions on Database Systems (TODS)
Synthesizing third normal form relations from functional dependencies
ACM Transactions on Database Systems (TODS)
Database abstractions: aggregation and generalization
ACM Transactions on Database Systems (TODS)
Equality and Domain Closure in First-Order Databases
Journal of the ACM (JACM)
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
Normal forms and relational database operators
SIGMOD '79 Proceedings of the 1979 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
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
On the Semantics of the Entity-Relationship Data Model
Proceedings of the 1st International Conference on the Entity-Relationship Approach to Systems Analysis and Design
Item Tracking Entity-Relationship Models
ER '81 Proceedings of the Second International Conference on the Entity-Relationship Approach to Information Modeling and Analysis
Properties of acyclic database schemes
STOC '81 Proceedings of the thirteenth annual ACM symposium on Theory of computing
The universal instance and database design
The universal instance and database design
A formal treatment of imperfect information in database management
A formal treatment of imperfect information in database management
ACM SIGMOD Record
SYSTEM/U: a database system based on the universal relation assumption
ACM Transactions on Database Systems (TODS)
On the properties and characterization of connection-trap-free schemes
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
One flavor assumption and gamma-acyclicity for universal relation views
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Dynamic query interpretation in relational databases
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Incomplete information and the join operation in database machines
ACM '87 Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow
Efficient optimization of simple chase join expressions
ACM Transactions on Database Systems (TODS)
On the correctness of representing extended entity-relationship structures in the relational model
SIGMOD '89 Proceedings of the 1989 ACM SIGMOD international conference on Management of data
Identifying Extended Entity-Relationship Object Structures in Relational Schemas
IEEE Transactions on Software Engineering
Representing extended entity-relationship structures in relational databases: a modular approach
ACM Transactions on Database Systems (TODS)
On the foundations of the universal relation model
ACM Transactions on Database Systems (TODS)
Maximal objects and the semantics of universal relation databases
ACM Transactions on Database Systems (TODS)
On Kent's “Consequences of assuming a universal relation” (Technical correspondance)
ACM Transactions on Database Systems (TODS)
The universal relation revisited (technical correspondence)
ACM Transactions on Database Systems (TODS)
Degrees of acyclicity for hypergraphs and relational database schemes
Journal of the ACM (JACM)
MAYBE algebra operators in database machine architecture
ACM '86 Proceedings of 1986 ACM Fall joint computer conference
ELFS: English language from SQL
ACM Transactions on Database Systems (TODS)
Answering queries in relational databases
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
Query processing for distributed databases using generalized semi-joins
SIGMOD '82 Proceedings of the 1982 ACM SIGMOD international conference on Management of data
Inclusion dependencies and the universal instance
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Reflections on Boyce-Codd Normal Form
VLDB '82 Proceedings of the 8th International Conference on Very Large Data Bases
LAURA: A Formal Data Model and her Logical Design Methodology
VLDB '83 Proceedings of the 9th International Conference on Very Large Data Bases
Universal Relation Views: A Pragmatic Approach
VLDB '83 Proceedings of the 9th International Conference on Very Large Data Bases
A Step by Step Method for Conceptual Data Analysis
SEEP '96 Proceedings of the 1996 International Conference on Software Engineering: Education and Practice (SE:EP '96)
Interpretation of statistical queries to relational databases
SSDBM'1988 Proceedings of the 4th international conference on Statistical and Scientific Database Management
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Many results in relational database theory on the structure of dependencies, query languages, and databases in general have now been established. However, neither (a) the reliance of these results on various assumptions, nor (b) the desirability or reasonableness of these assumptions themselves have been closely examined. These assumptions are nontrivial: examples include the universal relation assumption and the lossless join assumption.The purpose of the present paper is to clarify many of the existing assumptions, and point out weaknesses. This is desirable both to harden the statements of previous results, and to evaluate recent suggestions that certain assumptions (such as the acyclic JD assumption) may be useful for modeling "real world" databases. Specifically, studies are made of assumptions made for (1) universal relations, (2) functional dependency inference, and (3) decomposition theory. We show that:• Some assumptions (such as uniqueness of relationships among attributes) can be more powerful than they appear;• common treatment of FDs is sometimes inappropriate, and for example FD inferences such as {A → B, B → C} |= A → C can be incorrect;• the 'decomposition' approach to design may be hard to justify in real terms; and• Acyclic JDs may have drawbacks in eliminating ambiguity in queries and in modeling real enterprises.It is hoped that this exposition will help clarify some confusing issues in this field, and will lead to a better understanding of which assumptions are reasonable and useful in modeling the "real world".