1. XMLExtensible Markup Language By: Gaurav Poudyal

2. Overview • XML • Different XML Related Technologies • XHTML • XForms • XQuery • Conclusion

3. What is XML? • Markup language very similar to HTML • How do they differ? • HTML focuses on displaying data • XML focuses on describing the data • XML tags are not predefined as in HTML

4. Example Code • XML structures information • Code below is just information stored in XML tags <?xml version="1.0" encoding=""?> <journal> <message>Today is Wednesday and it’s windy.</message><br /> <message1>It is snowing outside</message1><br /> </journal>

5. XML • XML requires syntax just as in HTML 1) <?xml version="1.0" encoding=""?> 2) <journal> 3) <message>Today is Wednesday and it’s windy.</message> 4) <message1>It is snowing outside</message1> 5) </journal> • First line states XML version and the encoding • Tag journal is the root element • Lines 3 and 4 are child elements

6. XML • All tags must have a closing tag, unlike in HTML • XML tags are case sensitive • XML preserves the white space, unlike HTML Code: Today is Wednesday Displayed in html: Today is Wednesday Displayed in XML: Today is Wednesday

7. XML Elements • Elements can have relationships <class> <title>My Classes</title> <course>463</course> <subject>Client Server Web Applications <para>What is HTML</para> <para>What is XML</para> </subject> </class> • In the code above, class is the root element • Title, course, subject are child elements of class • Class is the parent element of title, course, subject • Title, course, subject are sister elements

8. XML with ASP • XML can be generated on server with ASP <% response.ContentType="text/xml" response.Write("<?xml version='1.0' encoding='ISO-8859-1'?>") response.Write("<class>") response.Write("<title>My Classes</title>") response.Write("<course>Coms 463</course>") response.Write("<subject>Client Server Web Applications</subject>") response.Write("<para>What is HTML</para>") response.Write("<para>What is XML</para>") response.Write("</class>") %> • Must be saved as a .asp file

9. XML Related Technologies Few that I am covering in this presentation • XHTML • XForms • XQuery

10. XHTML • XHTML is also known as Extensible Hypertext Markup Language • XHTML is similar to HTML with stricter rules • XHTML needs proper syntax and formats • Nested elements • Proper tag names • Closed tag elements • Quoted and lowercase attribute names

11. Code Example Properly nested code: <ul> <li>Book</li> <li>Article <ul> <li>Online Article</li> </ul> </li> <li>Print</li> </ul>

12. Code Example Proper tag names: • Tags should be all lowercase • Cannot be <email> and <Email> • Cannot be <body> and <BODY> • All tags must be closed at end <email> <body>How are you?</body> </email>

13. Code Example Lower case attribute names and quoted value • Attribute name “width” must be lowercase • Value must be quoted, either single or double quotes <table width = "50%">

14. XForms • XForms are also known as XML Forms • More affluent • More flexible

15. Code Example <xforms> <model> <instance> <course> <cname/> <cid/> </course> </instance> <submission id="form1" method="get" action="submit.asp"/> </model> <input ref="cname"> <label>Course Name</label></input><br /> <input ref="cid"> <label>Course Iden</label></input><br /><br /> <submit submission="form1"> <label>Submit</label></submit> </xforms> • XML is used in XForm to define the form data • XML is also used to store and transport the data • Model defines the data • Instance defines the data that will be collected. These data will be stored in XML tags and transported to the destination provided • Submission defines how the data will be submitted • Rest of code for user interface

16. Control Elements • Input • Output • Submit • Secret • Select1 • Select • Upload and more…

17. XQuery • XQuery is also known as XML Query Language • Way to query XML data • Supported by all databases • Find information, build reports and search web documents

18. Code Example • Function extracts data from file; doc(“classes.xml”) • Path expressions; doc(“classes.xml”)/classes/class/title • Predicates; doc(“classes.xml”)/classes/class[maxstudents>20] (classes.xml) <?xml version="1.0" encoding="ISO-8859-1"?> <classes> <class category="Computers"> <title lang="en">Client Server</title> <teacher>Dr. Syed</teacher> <term>Fall 2005</term> <maxstudents>20</maxstudents> </class> <class category="Business"> <title lang="en">International Business</title> <teacher>John Doe</teacher> <term>Fall 2005</term> <maxstudents>50</maxstudents> </class> </classes>

19. XQuery • Syntax rules should be followed in XQuery • All elements, variable, attributes must be valid XML names • String value must be in quotes • Conditional statements can be used, such as if-then-else

20. The EndThanks!