Αποθήκευση και διαχείριση XML με χρήση σχεσιακών συστημάτων βάσεων δεδομένων για εφαρμογές του παγκόσμιου ιστού ; XML storage and management using relational database management systems for internet applications

In nowadays, XML (eXtended Markup Language) is one of the most popular standard for representing data on the WEB. Although, in a wide spectrum of internet applications it is often required to manipulate information of semistructured nature, which may present variations according to different circumstances. Multidimensional XML (MXML) is an extension of XML suitable for representing, in a compact way, data that assume different facets, having different value and structure under different contexts, which are determined by assigning values to a number of dimensions. This doctoral thesis studies the problem of storing, updateing and querying MXML data using relational databases.Because of the great experience that already exists on the field of Relational Database Managment Systems (RDBMS), the problem of storing (XML Storage) and quering XML data using relational databases has been considered a lot and many related techniques have been developed. Following previous work on storing and quering XML in relational databases, we present the results of our research on storing (MXML Storage), navigating, querying and updating MXML documents using relational databases, taking into account the additional features of MXML compared to conventional XML. Those features stem from the incorporation of context into MXML.Investigating the problem of MXML storage, we present techniques and alternative relational schemas for storing MXML documents in relational databases, based on storage techniques previously proposed for conventional XML documents. Essential characteristics of the proposed techniques are the capabilities a) to reconstruct the original MXML document from its relational representation and b) to express MXML context-aware queries in SQL. Also, for all the proposed storage techniques, the way that the context is represented in the relational schema is a very important issue, as such a representation may facilitate the management and the navigation through the stored MXML data.As regards MXML quering, we introduce an ...