A Graphical Interface Formalism: Specifying Nested Relational Databases.
Gjpm Geert-Jan Houben, Jan Paredaens · TU/e Research Portal · 1988
An interface is considered as an automaton, for which the dynamics are represented by transitions on a set of states.Part of the actual state is currently represented by the screen.As such a program in Rl represents the possible dialogue between the user and the system.An overview of Rl, a language for specifying interfaces, is given.Rl is illustrated by specifying the R 2 -interface, which is a graphical interface for handling nested relational data.The definition of the R2-interface is such that queries on a database can be expressed in a way that suits the nested relational model, which means that objects at arbitrary levels can be specified directly, i.e. without referring to objects at other levels.