Normalization Theory for XML

Abstract

Abstract. Specifications of XML documents typically consist of typing information (e.g., a DTD), and integrity constraints. Just like relational schema specifications, not all are good -some are prone to redundancies and update anomalies. In the relational world we have a well-developed theory of data design (also known as normalization). A few definitions of XML normal forms have been proposed, but the main question is why a particular design is good. In the XML world, we still lack universally accepted query languages such as relational algebra, or update languages that let us reason about storage redundancies, lossless decompositions, and update anomalies. A better approach, therefore, is to come up with notions of good design based on the intrinsic properties of the model itself. We present such an approach, based on Shannon's information theory, and show how it applies to relational normal forms as well as to XML design, for both native and relational storage.

Extracting a largest redundancy-free XML storage structure from an acyclic hypergraph in polynomial time

“…Normalized XML storage schemas remove the possibility of redundancy with respect to constraints and typically make both retrieval and update more efficient. Thus, there has been a flurry of research work on normalization of XML documents [2,6,7,15,18,22,25,26,27]. This paper, which follows up on our previous work [7,18], is another step in this direction.…”

“…Because A does not appear in any node to the left Figure 12: The Path P between E i and E j of Lemma 4. 15 and BCV 10 in Figure 4 …”

“…By way of comparison with the XML normalization work of others [2,6,15,22,25,26,27], we point out that our approach differs significantly. Not only have these other researchers defined their FDs, and thus their normal forms, differently, the basis of our approach is also different from theirs.…”

Formal Framework of XML Document Schema Design

“…The native XML database stores XML documents directly without performing any conversion or reformatting the XML documents into another format thus reduce processing time and provide better performance. However, native XML database is still in its infancy and not as mature as traditional databases (e.g., relational database), hence many important problems and questions remain unanswered, especially on the principles of XML database design (Arenas, 2006;Schewe, 2005;Libkin, 2007).…”

Generating the fewest redundancy-free scheme trees from acyclic conceptual-model hypergraphs in polynomial time

“…By way of comparison with the scheme-tree normalization work of others (especially in the context of XML [1,4,9,15,16,17,18]), we point out that our approach differs significantly. Not only have these other researchers defined their FDs, and thus their normal forms, differently, the basis of our approach is also different from theirs.…”