We define the query language Vizla, in which answers to queries are built up by pointing to representations of sets and functions in a conceptual model of the data base of an application, and to iconic identifiers of computational operators or control constructs. At its present stage of development the primary use of Vizla is in the validation of conceptual models of information systems, but it is to be developed into a user interface to SF, a prototyping language for information and control systems. Moreover, it can be regarded as a visual programming language in its own right. As such it is based on abstract data types.
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