Iconic SQL: Practical issues in the querying of databases through structured iconic expressions

We report on an iconic interface that implements a restricted subset of SQL commands for querying a database. Database queries and the query language's tokens (verbs, adjectives, etc) are represented by icons. To construct a query, the user composes structured iconic expressions according to the grammar of the iconic language. The language and grammar include rules for iconic construction (Quadral Composite Icons and Serial Composite Icons). In brief, the user visually queries the database by issuing structured iconic queries composed in a systematic manner. The paper describes the syntactic and semantic principles behind structured iconic expressions and the way that these principles have been implemented in an iconic interface. User evaluation is informally reported, and the role of metaphor in the design and interpretation of icons is discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.