Towards an ODMG-Compliant Visual Object Query Language

摘要

We describe the design, implementation and user evaluation of Quiver, a graph-based visual query language for object databases. The design goals of QUIVER include compliance to standards, comprehensive representational power, and consistency of visual representation. Compliance to standards is achieved through Quiver queries being translated to OQL, the standard query language proposed by the Object Data Management Group (ODMG). Comprehensive representational power is gained by Quiver supporting a significant number of object database constructs, including objects, literals, attributes, relationships, structures, collections, operations, (aggregate) functions, and subqueries. Consistency of visual representation is pursued by assigning similar visual representations to constructs with similar functionality, as well as by minimising the use of text in Quiver queries. The language is implemented as a visual front-end to the O_2 object database system. Results of a user evaluation suggest that users find it easier to formulate correct queries in Quiver than in OQL.