Virtual Schemas in Visual Interfaces to Databases

Virtual Schemas are part of the visual information retrieval system called Mavigator. The system is dedicated to naive users (computer non-professionals) and allows them to retrieve information from any data source, in particular, from objectoriented and XML-oriented databases. A significant problem related to all browsing tools is a way of presenting database schema graph. In many cases, there is a need to customize data-base schema, in particular, changing some names, adding new associations or removing some classes. Virtual Schemas allow creating a virtual customized version of existing database schema and navigate within the database according to this schema. Schema customization options include creating virtual association and virtual attributes, hiding/showing particular classes and renaming some schema items.