Download
slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Introduction to XML PowerPoint Presentation
Download Presentation
Introduction to XML

Introduction to XML

257 Vues Download Presentation
Télécharger la présentation

Introduction to XML

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Introduction to XML This is not an XML class, but for those who do not know XML, here is a very brief introduction…

  2. What is XML? • XML is a standard published by the W3C • It is used to describe markup languages (“tag sets”) • It is application- and platform-independent • It handles multiple character sets (unicode) • It is a text format which is easy to read

  3. How Does XML Work? • XML takes a stream of text characters, and allows them to be interpreted as a tree structure • It combines the properties of documents with the structure of object-oriented systems

  4. Text Text Text Text Text Text Text Text Text Text Text = XML “element” = string, code, or number

  5. XML Elements • XML elements have names, and a specific content which is described either in a DTD or (as for SDMX-ML) in an XML schema • XML elements can contain other elements, or values, or both (or neither) • They have a start tag <NameOfElement> and an end tag </NameOfElement> • They can have additional properties, called attributes: <NameOfElement NameOfAttribute=“ValueOfAttribute”>

  6. XML Elements (cont.) • In an XML document, everything between an element’s start tag and end tag is contained in that element: <ElemA> <ElemB>Some Text</ElemB> <ElemC>Some Other Text</ElemC> </ElemA> • Here, ElemA contains ElemB and ElemC, which in turn contain text.

  7. XML Documents • XML documents have their exact contents (elements, attributes, numeric, string, and coded data) described in a separate XML file called an XML Schema • XML documents can be validated with a generic processor called an “XML Parser” • XML documents can be rendered into tree objects in memory, for processing, by many different software tools

  8. Why XML is so Popular • XML is popular because: • it allows very complex sets of structured data to be transmitted over the internet as a simple stream of characters (a document), but… • It allows processing of that simple stream as a rich object model in the receiving application • XML is ubiquitous on the Internet, and is the basis of all web-services applications