SYSTEM/U: a database system based on the universal relation assumption
ACM Transactions on Database Systems (TODS)
A high-level user interface for update and retrieval in relational databases—language aspects
SIGMOD '85 Proceedings of the 1985 ACM SIGMOD international conference on Management of data
A normal form for relational databases that is based on domains and keys
ACM Transactions on Database Systems (TODS)
Update semantics of relational views
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)
On Kent's “Consequences of assuming a universal relation” (Technical correspondance)
ACM Transactions on Database Systems (TODS)
Relaxing the universal relation scheme assumption
PODS '85 Proceedings of the fourth ACM SIGACT-SIGMOD symposium on Principles of database systems
Principles of Database Systems
Principles of Database Systems
Synthesizing independent database schemas
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
A transportable natural language database update system
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
Improving database schemes by adding attributes
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
Universal Relation Views: A Pragmatic Approach
VLDB '83 Proceedings of the 9th International Conference on Very Large Data Bases
The universal instance and database design
The universal instance and database design
Theory of Relational Databases
Theory of Relational Databases
View updates in relational databases with an independent scheme
ACM Transactions on Database Systems (TODS)
Updating relational databases through weak instance interfaces
ACM Transactions on Database Systems (TODS)
A Universal Relation Data Model with Semantic Abstractions
IEEE Transactions on Knowledge and Data Engineering
Decomposing Heterogeneous Inter-Entity Relationship Updates
IEEE Transactions on Knowledge and Data Engineering
An Extended Authorization Model for Relational Databases
IEEE Transactions on Knowledge and Data Engineering
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A database system that is based on the universal relation (UR) model aims at freeing its users from specifying access paths on both the physical and on the logical levels. All information about the logical structure of the database (i.e., its conceptual scheme) is hidden from users; they need only to know the attribute names, which now carry all the semantics of the database.Previous work on UR interfaces has concentrated on the design and implementation of query languages that serve to facilitate retrieval of data from a relational database. On the other hand, updates are always handled as before, which means that users still have to know the logical structure of the database in case they want to insert, delete, or modify tuples.In this paper the concepts underlying a UR interface, which is really “universal,” are presented; it is based on the UR model, and it permits not only queries but also updates: Combinations of attributes that may participate in an update-operation ("objects") have to be specified during the design phase of the database, and are then embodied into the database scheme by an extended synthesis algorithm. They form the basis for any insertion or deletion operation. A precise definition of “insertable” tuples, and of the insert- and delete-operation in this new context, is given. It is then shown that these operations modify a database state in such a way that a representative instance always exists. This is accomplished by providing a more detailed version of Sagiv's uniqueness condition and by exploring the structure of nonunique objects. Since the underlying database always has a representative instance, this instance can be used to define the window function for retrieval. It is shown that it is still possible to compute windows by a union of minimal extension joins.