1. School of Computing and Management Sciences © Sheffield Hallam University To understand the Oracle XML notes you need to have an understanding of all these aspects of XML: –Well-formedness –Validation –XML Schemas –XML structures, nodes –what XPATH is –what DOM is If you know all these things well, skip this lecture and do the Oracle XML lecture XML

2. School of Computing and Management Sciences © Sheffield Hallam University Extensible Markup Language (XML) “A Web-based markup language that could give EDI the kick-start it needs…” EDINews XML is a meta language which allows users to create their own markup language which can describe one particular content It can run on any platform Closely related to HTML, via SGML Non proprietary - W3C Is an enabling technology, allowing heterogeneous systems to communicate both within and between organisations Chang et al (2000) state “XML is not an application but an enabling technology” XML

3. School of Computing and Management Sciences © Sheffield Hallam University Separates out three aspects: –Content The data stored in a.XML file –Structure Validation rules stored either in: –Document Type Definition: DTD –A Schema –Display CSS or XSL Programmatically through the DOM XML

4. Content XML Structure XML-Schema DTD Display XML DOM CSS XSL XPath (point to part of tree) XSLT (transform the tree) XSL-FO (format in pages) Vocabularies based on XML SMIL Voice XML SVG HGML CML…. Other XML topics XLink XPointer XML QUERY XML & Databases Web services WSDL UDDI SOAP.NET ASP.NET Visual Studio.NET Java, C# The XML Environment Lafferty, 2002

5. School of Computing and Management Sciences © Sheffield Hallam University NODES AND THE ROOT NODE –XML documents are Hierarchical and can be thought of as consisting of a set of nodes –connected by branch-leaf relationships and with a single ultimate start, which is called the root –Element nodes can have attributes and/or content, which can be considered leaf –The node structure of XML is important for traversing or selecting nodes, processing with XPATH XML building blocks

6. School of Computing and Management Sciences © Sheffield Hallam University Elements –eg: Attributes –Eg: Processing Instructions (PI) –Eg: XML building blocks

7. School of Computing and Management Sciences © Sheffield Hallam University Entity Reference (aka escape sequences) –eg: <& é – my salary is < £1000000 Comments –Eg: Marked Sections –Eg: <![CDATA[ – >>>>>>>>> XML building blocks

8. School of Computing and Management Sciences © Sheffield Hallam University Document Type Declarations –Eg: document type declaration contains or points to declarations that provide a grammar for a class of documents Namespaces –Eg:<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" –xmlns="http://homepages.shu.ac.uk/~cmpl4" –…….. XML building blocks

9. School of Computing and Management Sciences © Sheffield Hallam University Schema –Does not mean the same as SCHEMA in an RDBMS environment. –Is a set of rules that describes what makes data in any XML valid –A newer, more flexible version of DTD –Things like datatypes, value constraints –Stored Once referred to many times in XML files: <Schema name="StockSchema" xmlns="urn:schemas-microsoft-com:xml-data" xmlns:dt="urn:schemas-microsoft-com:datatypes">....... XML building blocks

10. School of Computing and Management Sciences © Sheffield Hallam University Schema XML building blocks

11. School of Computing and Management Sciences © Sheffield Hallam University DOM –A standards based definition of what an XML document looks like in memory –Provides access through object-oriented abstract interface specifications for XML documents –All the document is in memory at once SAX –also allow programmatic access to XML, but is streams based. –In SAX the document is read from the beginning and parsing proceeds sequentially. –You can deal with large documents –Writing code is more difficult XML Access

12. Hundred miles an hour tour of: –http://www.shu.ac.uk/schools/cms/teaching/hl1/xm l/xml2000.dochttp://www.shu.ac.uk/schools/cms/teaching/hl1/xm l/xml2000.doc Other material –http://www.shu.ac.uk/schools/cms/teaching/hl1/xm lnotes.htmhttp://www.shu.ac.uk/schools/cms/teaching/hl1/xm lnotes.htm –http://www.w3schools.com/xml/xml_whatis.asphttp://www.w3schools.com/xml/xml_whatis.asp –http://www.oracle.com/technology/tech/xml/pdf/42 7.pdfhttp://www.oracle.com/technology/tech/xml/pdf/42 7.pdf XML tutorial