Technical Report CS0412

Title: Unifying Entity-Relationship and Universal Relation Approaches to User Interfaces
Authors: V.M. Markiwitz and J.A. Makowsky
Abstract: We propose to unite the Entity-Relationship(ER) and Universal Relation(UR) approaches to user interfaces. UR schemas are difficult to design, mainly because most of the explicit structure of the schema is implied (concealed) by the attribute names, and are not able to communicate with the users. Unlike UR schemas, ER diagrams are easy to understand and use, and back techniques of paraphrasing the interpretation given by the system to the user's query. We present an ER oriented methodology for the design of UR schemas. The proposed mapping of ER diagrams to UR schemas solves the problem of multiple role representation by UR schemas. A UR schema is said to be ER-consistent, either if it is the translate of an ER diagram, or if it ispossible to translate it back into an ER diagram. An algorithm is presented which decides if a UR schema is ER-consistent.

Automatic or guided navigation is important for users with partial knowledge of the database structure. Such users could assume the existence of some relationship-set among certain entity-sets. The main concern of this UR interfaces is to find the most plausible derivation suiting such a relationship-set. The core of the UR methodology is the the termination of(maximal) objects, on which these derivations are based; we show that the ER oriented design, embodied by ER-consistency, simplifies their designation.

The user interface we pre proposing combines the ER modeling and communication capbilities with the UR methodology for automatic derivation of virtual relationships. Such an interface could back usersystem interaction in an effective way by cooperating in solving ambiguities and disparities between its beliefs and those of its users.

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