====== eXtensible Markup Language (XML) ======
===== Before the lab =====
Reading: 
  * [[http://www.w3schools.com/xml/xml_whatis.asp|XML]] 
  * [[http://www.w3schools.com/dtd/default.asp|DTD]]
  * [[http://www.w3schools.com/schema/default.asp|XSD]]
  * [[http://www.w3schools.com/xpath/default.asp|XPath]]
  * [[http://www.w3schools.com/xml/xml_xsl.asp|XSL]]
  * [[#if_you_want_to_know_more|If you want to know more...]]

===== Introduction =====
Lectures:
  * {{http://home.agh.edu.pl/~wta/semweb/geist-semweb-uri.pdf|Semantic Web: 1.5 - Unicode and URI}}
  * {{http://home.agh.edu.pl/~wta/semweb/geist-semweb-xml.pdf|Semantic Web: 2 - XML}}





===== Lab instructions =====

The lab is divided into sections. You should allow aprox. 10 minutes for each section. 
However, note that the tasks are increasingly difficult and latter sections may be more time-consuming than the former ones.

==== - Warm-up: Well-formedness of the XML ====
8-) Determine which of the following XML documents is well-formed. If a document is well-formed,
show its corresponding tree model. If it is not well-formed, explain why not. You may assume that all
of these documents are intended to be XML 1.0 documents, and thus the declaration is not needed.

//NOTE: Assume that the prolog of the documents is present and the following lines are the body of the document//.\\
<code>
  - <a><b/><a>
  - <a><b>foo</b></a><a>bar</a>
  - <a><b>foo</b><b>bar</a>
  - <a><b><c>foo</b>bar</c></a>
  - <a/><b>foo</b><b>bar<b>
  - <a><b><c>foo</c>baz<c>bar</c></b></a>
  - <a x="1" X="2"><b>foo</b></a>
  - <a x="1"><b x="2">foo</b></a>
  - <a x="1" y="2" x="3"><b>foo</b></a>
  - <a><b x="3"><c y="1">foo</c><c>bar</c></b></a>
</code>

==== - Creating XML document ====
8-) Modify the code below to describe the best book from your bookshelf:

<code xml>
<book>
  <author>Grigoris Antoniou</author>
  <author>Frank van Harmelen</author>
  <title>A Semantic Web Primer</title>
  <date>2008-10-09</date>
  <publisher>The MIT Press</publisher>
</book>
</code>

  * You can modify the markup and hierarchy.

==== - DTD ====
  * Using a text editor, define a [[http://www.w3schools.com/dtd/default.asp|DTD]] definition for your XML syntax. Put it in the report 8-)
  * You can define DTD definition inside XML file: \\ <code>
<?xml version="1.0" ?> 
<!DOCTYPE root [
]>
XML content
</code>

==== - Validating XML with DTD ====
  * Test your XML against defined DTD using [[http://www.xmlvalidation.com/index.php|online validator]] - **it requires embedded DTD**. \\ or
  * You can also test your XML using //xmlstarlet// command: \\ Testing xml file against external DTD definition file use:<code>
xmlstarlet val -e -d file.dtd file.xml
</code>or when you use embeded DTD definition use:<code>
xmlstarlet val -e -E file.xml
</code>


==== - XSD ====
  * Using a text editor, define an [[http://www.w3schools.com/schema/default.asp|XSD]] definition for your XML syntax. Put it in the report 8-)

==== - Validating XML with XSD ====
  * Test your XML against defined XSD using:
    * using //xmlstarlet// command:<code>
xmlstarlet val -e -s file.xsd file.xml
</code> \\ or
    * [[http://tools.decisionsoft.com/schemaValidate|XSD online validator]] \\ or
    * [[http://www.xmlme.com/Validator.aspx|XML Schema Validator]]

==== - XPath ====
  * Go to the [[http://www.xmlme.com/XpathTool.aspx|XPath Tool]]
  * Paste your XML code in the prepared tesxtfield
  * Build and test the XPathc for the following:
    * find the lastnames of all students,
    * find all lastnames of members from a given group,
    * find an address of the second member from a given group,
    * find all the cities of all members,
    * find all the students which are older/younger than a given age,
    * find a lastname of your group leader.
  * Put the queries in the report 8-)

==== - XSLT: XML -> HTML ====
  * Go to the W3Schools' [[http://www.w3schools.com/xsl/tryxslt.asp?xmlfile=cdcatalog&xsltfile=cdcatalog|online XSLT editor]].
  * Paste your XML code in the left textarea
  * Modify the XSLT code in the right text area to display your data in a table. Make experiments.
===== Control questions =====
  * What are the required elements of XML file?
  * What is an empty element?
  * Does the XML have any predefined tags?
  * How to define a comment?
  * Is the XML platform dependent?
  * What is a CDATA section in XML file?
  * What is the meaning of the colon within tag name?
  * What is the DTD?
  * What is the XSD?
  * Which language (DTD or XSD) is more expressive?
  * What is the XPath?
  * Does the XPath allow for nested queries?
  * What is XSLT for?
  * How does the XSLT work?
===== If you want to know more =====
    * [[http://www.w3.org|www.w3.org]]
    * [[http://validator.w3.org|validator.w3.org]]
    * [[http://www.xml.org|www.xml.org]]
    * [[http://www.xml.com|www.xml.com]]
    * [[http://xml.coverpages.org|xml.coverpages.org]]
    * [[http://www.w3schools.com/|www.w3schools.com]]
    * [[http://www.ibm.com/developerworks/xml|www.ibm.com/developerworks/xml]]
    * [[http://xml.oreilly.com/xml|xml.oreilly.com]]
    * [[http://developer.mozilla.org/en/docs/Main_Page|Mozilla Developer Center]]
    * xml schemas: [[http://www.ibm.com/developerworks/library/x-schematips/?ca=dgr-lnxw07x-schematips&S_TACT=105AGX59&S_CMP=GRsitelnxw07|Ten XML schemas you should know]]
    * CSS: [[http://meyerweb.com/eric/css/|Eric Meyer]]