Providing a Method Based on the Path Indexes in Optimizing XML Queries

In this paper, initially, the description and the processing way of the existing queries and languages in this field is performed and a base is graded for the new method by classifying the present methods and evaluating on strengths and weaknesses of each method. This three-step approach is proposed to improve previous methods. The method involves three steps:

1. First step: Simplifying query and reducing the searching area.

2. Second step: Producing a result table as a guide for the query processor.

3. Third step: Processing the document nodes according to the guide table produced in the previous step.

This three-step method can prove its ability compared to the previous methods. The method is developed so that it has the efficiency for complicated multi-branches queries. Then, it is tried to optimize the method, considering the concept of the extraction points. During the three steps, useless nodes – the nodes that either do not make a response for the user, or return a repetitive one – were used so much; using such nodes is reduced by introducing an index called level index.