Developing XML Documents with Guaranteed “Good” Properties

Abstract

Many XML documents are being produced, but there are no agreed-upon standards formally defining what it means for complying XML documents to have “good” properties. In this paper we present a formal definition for a proposed canonical normal form for XML documents called XNF. XNF guarantees that complying XML documents have maximally compact connectivity while simultaneously guaranteeing that the data in complying XML documents cannot be redundant. Further, we present a conceptual-model-based methodology that automatically generates XNF-compliant DTDs and prove that the algorithms, which are part of the methodology, produce DTDs to ensure that all complying XML documents satisfy the properties of XNF.

Since we do not address issues beyond hierarchical structure in this document, we discuss the issues in terms of DTDs rather than XML-Schemas.

The idea of XNF is based on nested normal form as defined in [MEN96] and is also related to other similar nested normal forms such as those surveyed in [Mok].

The class of documents we are considering is certainly large, but also certainly not all-inclusive. We do not, for example, consider text documents where the order of textual elements is important.