A Direct Approach to Holistic Boolean-Twig Pattern Evaluation

XML has emerged as a popular formatting and exchanging language for nearly all kinds of data, including scientific data. Efficient query processing in XML databases is of great importance for numerous applications. Trees or twigs are the core structural elements in XML data and queries. Recently, a holistic computing approach has been proposed for extended XML twig patterns, i.e., B-Twigs (Boolean Twigs), which allows presence of AND, OR, and NOT logical predicates. This holistic approach, however, resorts to pre-normalization on input B-Twig queries, and therefore causes extra processing time and possible expansion on input queries. In this paper, we propose a direct, holistic approach to BTwig query evaluation without using any preprocessing or normalization, and present our algorithm and experimental results.