XML A Language Presentation

Outline 1. Introduction 2. XML 2.1 Background 2.2 Structure 2.3 Advantages 3. Related Technologies 3.1 DTD 3.2 Schemas and Data Types 3.3 XSL, XQL and CSS 3.4 XLink and XPointer 4. Conclusions 5. Questions

1. Introduction XML – eXtensiable Markup Language Special way of transferring data Plain text with meaningful structure Platform and application independent Many technologies built on top of XML

2. XML A sample XML document

2.1 Background Created by the SGML editorial Review Board in 1996 Specific design goals Subset of the Standard Generalized Markup Language or SGML Looks similar to HTML

2.2 Structure Uses storage units called entities, such as elements and attributes Tree layout: root, parents and children All entities are defined by explicit markup Strict rules for defining syntax

2.2 continued… Unlike HTML, XML elements and attributes are defined by the author Namespaces help avoid name collisions Usually, authors web page is used Namespaces can be applied to specific parts of the document and not others

2.3 Advantages Data is independent of applications Can be interpreted in anyway the author intends The way the data is viewed/styled is independent An XML document is self describing

3. Related Technologies How is XML used by or with applications?

3.1 Document Type Definition (DTD) Defines structure Allows parsers and applications to read the document Can be with the document or in an external file DTD’s are an important part of XML documents

3.2 Schemas and Data Types Alternate to DTD’s Required to define data for applications Can define data types Scope exists Inheritance and sub-classing

3.2 Continued… A sample schema

3.3 XSL, XQL and CSS Define how the data is displayed Can filter or sort data Used to manipulate, create, control, or manage document and data Transformations into HTML or other XML documents

3.3 continued… A sample Style Sheet

3.4 XLink and XPointer Creates links to other documents Creates links to specific parts of documents or other resources Can be used to create documents very similar to HTML Vital aid due to the lack of predefined elements

4. Conclusions Simple platform and application independent way of transferring data General purpose, is it a language? Many related and important technologies Gives author/interpreter complete control Appearing everywhere, have you seen it?

5. Questions?