In this chapter, the research background is discussed. This includes XML model, XML query languages, XML schema languages, XML Application Program Interface, XML documents types, XML data storage approaches, relational database model, and the similarities and differences between XML model and relational database model. Finally the chapter summary is given.
Ever modified an XML schema? Ever broken something while fixing a bug or adding a new feature? As with any piece of engineering, the more complex a schema is, the harder it is to maintain. In other domains, unit tests dramatically reduce the number of regressions and thus provide a kind of safety net for maintainers. Can we learn from these techniques and adapt them to XML schema languages? In this workshop session, we develop a schema using unit test techniques, to illustrate their benefits in this domain.
Background: We wish to introduce a new chemical format called UCM (Universal Chemical Markup). The format is based on XML (Extensible Markup Language) and its first version focuses on recording chemical structures and their properties. Results: UCM currently supports structures containing isotopes, ions and various types of bonding including delocalized bonds. Properties can be expressed by combining UCM with UnitsML (Units Markup Language). Using UnitsML one defines quantities with scientific units, and then refers to them in UCM when recording property values. Users can also add literature references with BibTeXML (BibTeX Markup Language) and annotate the recorded data using plain text or XHTML (Extensible Hypertext Markup Language) descriptions. In contrast to presently available general-purpose chemical formats, UCM offers built-in validation, which combines both grammar and pattern-based XML schema languages. Thus, all recorded data can be precisely validated by UCM schemas in standard XML validators. Conclusions: We developed the structure for UCM from scratch on the basis of an analysis described in our previous article. Starting from scratch allowed us to integrate BibTeXML, UnitsML and XHTML as well as chemical line notations and identifiers into UCM. It also helped us to avoid unnecessary redundant parts and create the implementation that aims to minimize ambiguity and is designed to be easily extensible in the future.
Background: We wish to introduce a new chemical format called UCM (Universal Chemical Markup). The format is based on XML (Extensible Markup Language) and its first version focuses on recording chemical structures and their properties. Results: UCM currently supports structures containing isotopes, ions and various types of bonding including delocalized bonds. Properties can be expressed by combining UCM with UnitsML (Units Markup Language). Using UnitsML one defines quantities with scientific units, and then refers to them in UCM when recording property values. Users can also add literature references with BibTeXML (BibTeX Markup Language) and annotate the recorded data using plain text or XHTML (Extensible Hypertext Markup Language) descriptions. In contrast to presently available general-purpose chemical formats, UCM offers built-in validation, which combines both grammar and pattern-based XML schema languages. Thus, all recorded data can be precisely validated by UCM schemas in standard XML validators. Conclusions: We developed the structure for UCM from scratch on the basis of an analysis described in our previous article. Starting from scratch allowed us to integrate BibTeXML, UnitsML and XHTML as well as chemical line notations and identifiers into UCM. It also helped us to avoid unnecessary redundant parts and create the implementation that aims to minimize ambiguity and is designed to be easily extensible in the future.
This paper presents a refined taxonomy of XML schema languages based on the work by Murata et al., 2005. It can be seen as first building block for a more elaborate formal analysis of XML and its accompanied specifications, in this case: XML schema languages such as DTD, XSD and RELAX NG.
The eXtensible Markup Language (XML) is a data set to represent data in a format that is both human readable and machine readable. For XML documents to provide understanding about data exchange between applications, XML schema documents should be validated against the schema language. Most existing schema metrics were implemented differently in Document Type Definition (DTD), XML Schema Definition (XSD) and Regular Language for Next Generation (RNG) but never compare XML schema languages on any metric. Hence this paper compared three different schema languages on Improved Entropy Metric (IEM) using the Number of Attributes (NA), Number of Equivalence Class (NEC), Frequency Occurrence of Class (FOCi) and Number of Elements (NE). The proposed metric was applied on real schemas documents data are acquired from Web Service Description Language (WSDL) and implemented in DTD, XSD and RNG. The result showed that RNG reduce complexity of class elements, reflect strong support for class elements to appear in any order which showed more reusability and flexibility traits and overall understanding of the schema documents becomes much easier because RNG can be algorithmically converted and partner with other schema languages therefore this reduces maintenance effort. Keywords— XML Schema Language, Schema Documents, Schema Metrics
Comparative analysis of six XML schema languages
