Transformation of XML Data into XML Normal Form
Tadeusz Pankowski, Tomasz Piłka · 2009
Normalization as a way of producing good database designs is a well understood topic for relational data. In this paper we discuss the problem of eliminating redundancies and preserving data dependencies in XML data when an XML schema is normalized. Normalization is one of the main tasks in relational database design, where 3NF or BCNF, is to be reached. However, neither of them is ideal: 3NF preserves dependencies but may not always eliminate redundancies, BCNF on the contrary – always eliminates redundancies but may not preserve constraints. In this paper we consider the possibility of achieving both redundancy-free and dependency preserving form of XML schema. We show how the XML normal form can be obtained for a class of XML schemas and a class of XML functional dependencies. We relate our approach to the decomposition algorithm proposed by Arenas and Libkin in [1]. Povzetek: Razvita je metoda pretvorbe XML podatkov v normalizirano obliko s poudarkom na odstranjevanju redundanc. 1