{'fraction_non_alphanumeric': 0.0164756446991404, 'fraction_numerical': 0.0, 'mean_word_length': 5.292792792792793, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Adaptability of Methods for Processing XML Data using Relational Databases - the State of the Art and Open Problems

XML technologies have undoubtedly become a standard for data representation and manipulation and are widely used in various spheres of human activities. Thus it is inevitable to propose and implement efficient techniques for managing and processing XML data. A natural alternative is to exploit tools and functions offered by relational database systems. Unfortunately this approach has many objectors who point out especially its inefficiency caused by structural differences between XML data and relations. On the other hand, relational databases have long theoretical and practical history and represent a mature and reliable technology, i.e. they can offer properties that no native XML database can offer yet. On this account we believe that the database-based XML processing should be further studied and enhanced. In this paper we study techniques which enable to improve XML processing based on relational databases, so-called adaptive or flexible mapping methods. First of all, we discuss reasons why these techniques are important and promising. Secondly, we provide an overview of existing approaches, we classify their main features, and sum up the most important findings and characteristics. Finally, we discuss possible improvements and corresponding key problems.