Evaluating Object-Oriented Query Languages

Different query languages have been implemented and others proposed for object-oriented database systems. Evaluating and comparing these languages has been difficult due to the lack of a frame of reference. This paper establishes such a framework using four dimensions: support of ob object-orientation, expressive power, support of collections, and usability. Each dimension is defined in terms of a number of criteria. The criteria are, in turn, explained using example queries written in a concise, expressive, and clear query notation: object comprehensions. These same examples also demonstrate the process of evaluating a query language by showing how the criteria can be assessed. An evaluation based on the proposed framework reveals that many well-known query languages do not meet all the criteria. The evaluation framework can also be used constructively in improving existing query languages and directing new query language design