13. Query Processing and Optimization in A-DB
Leonidas Fegaras · 2004
Summary. The advent of web databases and XML has sprouted a new interest in object-oriented database technology for storing and manipulating semi structured data. Still lacking from object-oriented databases is a suitable framework for query processing and optimization that meets the perfor mance requirements of these applications. We present an effective frame work with asolid theoretical basis for optimizing query languages. Our cal culus, called the monoid comprehension calculus, captures most features of ODMG OQL and is a good basis for expressing various optimization al gorithms concisely. As a realistic domain to demonstrate the effectiveness of our framework, we have chosen the domain of XML query processing. We present a framework for storing XML data and for translating XML queries into OQL queries. Instead of inventing yet another semi-structured algebra for expressing our translations, the target of our transformation rules is OQL code, which is optimized without any fundamental extension to the existing optimization framework.