The authors present a graphical query language, GOQL (Graphical Object Query Language), for object-oriented data base systems, in general, and the object model of ODMG 2.0, in particular. A detailed literature survey of related work is given, and an analysis methodology that allows the evaluation of such languages is proposed. Moreover, the user's view of GOQL is presented. The user's view provides a graphical schema that does not contain any of the perplexing details of an object-oriented database schema; it also provides a graphical interface that supports ad hoc queries for object-oriented database applications. Because there is a direct correspondence between the features of GOQL and OQL (GOQL supports all the features of OQL), the language can be used as an alternative graphical interface to OQL. Thus, GOQL allows users to express queries graphically ranging from simplistic to complicated ones. Among the features provided/supported by the language are: a 2D colour interface, methods, predicates, Boolean and set operators, arithmetic expressions, existential/universal quantifiers, aggregate functions, group by and sort operators, functions, and subqueries. In this article, we illustrate through examples both the user's view and the query mechanism of GOQL. This work represents the completion of work that was partially presented in earlier articles.
|Number of pages||7|
|Journal||International Journal of Computers and Applications|
|Publication status||Published - 2002|
- Graphical query languages
- Object-oriented databases