VISUAL is a graphical icon-based query language designed for scientific databases where visualization of the relationships are important for the domain scientist to express queries. Graphical objects are not tied to the underlying formalism; instead, they represent the relationships of the application domain. VISUAL supports relational, nested, and object-oriented models naturally and has formal basis. In addition to set and bag constructs for complex objects, sequences are also supported by the data model. Concepts of external and internal queries are developed as modularization tools. A new parallel/distributed query processing paradigm is presented. VISUAL query processing techniques are also discussed.