SNAP: A graphics-based schema manager

The SNAP system provides interactive, graphics-based access to Schemas of the IFO database model, supporting the varied activities of schema design, schema browsing, and the specification of selection-type queries. The system uses a novel representation for Schemas and includes a variety of abstraction mechanisms which encourage users to design and view Schemas in a modular fashion. It also supports numerous capabilities for the simultaneous display of large amounts of information about the underlying schema, queries being specified, and answers to those queries. A prototype of the system which demonstrates the basic features of the user interface has been implemented.