Visual query of completely encapsulated objects

This paper presents a general purpose object query system and language, called QBI (Query by Icon), that involves the manipulation of icons for composing a query. It requires neither special knowledge of the content of the underlying database or understanding of the details of the database schema, hence it is equally useful to both unsophisticated and expert users. A user perceives the database as classes of objects and generalized attributes while the system internally maintains a schema of the underlying database rich in semantic information. No relationship specification is required for composing a query. Furthermore, automatic natural language feedback and cardinality constraints analysis assist users in query specification