Indexing Semi-structured Data for Efficient Handling of Branching Path Expressions

One of the major challenges in development of indexing techniques for semi-structured data is related to how to index the data structural properties. The main issue is how to efficiently handle branching path expressions without suffering from undesired growth of query processing costs and index file sizes. Several proposals for indexing semi-structured data can be found in the literature. However, in order to reduce index file sizes, most of them do not index or handle branching path expressions. Considering those ones that do that, they usually suffer from high query processing costs and large index file sizes. In such a context, this paper proposes a path-based indexing technique for semi-structured data, which deals with a well-defined class of branching path expressions. As evinced by experimental evaluation, the adoption of the proposed technique results in excellent query processing time and generates index file sizes close to data input file sizes.