lbsc 670 organization of information. review metadata models dublin core metadata standards dublin...
TRANSCRIPT
LBSC 670
Organization of Information
Review
• Metadata models• Dublin Core
• Metadata Standards• Dublin core, MARC
• Encoding Schemes• HTML, XML, MARC…
• Advanced metadata concepts• Schemas, application profiles
Questions?
INLS 520 – Fall 2007Erik Mitchell
INLS 520 – Fall 2007Erik Mitchell
Today
• Guest speakers:– Metadata and information organization in digital
libraries
• eXtensible Stylesheet Language:– Learning the nuts and bolts of metadata
transformation
Guest Speakers
• Jennine Kneiss• Thomas Whittaker
INLS 520 – Fall 2007Erik Mitchell
Anatomy of a Digital Library
Connecting structure and style
CSS
XHTML
Semantics & structure
Design & interactivity
XSL
Decision making
Programming 101
• Definition:– The process of developing a step-by-step
schematic for address a specific task
– The process of organizing these steps using a specific encoding system
– The manipulation of data to serve a specific information need
Compiled Vs Scripting
Definitions
• Programming Language• “A formal language used to write instructions that can be
translated into machine language and then executed by a computer.” (definitions)
• Scripting Language• Run-time (does not require compilation)• Restricted context (requires a specific environment)• Functional / Object oriented • Definitions
• Compiler / Interpreter• A program that builds and executes a program.
Compilers create a self-executable file, interpreters read a text script at run-time
The programming process
• Analyze the problem• What do you want your program to do?• What are your users expecting, what data do you have?
• Plan program flow/logic • What steps need to occur, in what order?• Useful tools include Step-Form, flowcharts, and
pseudocode• Code the program
• Create variables, routines, functions• Compile/run the program• Test, verify• Release
eXtensible Stylesheets
eXtensible Style Language (XSL) is a metadata schema that is encoded using XML and interpreted by Web-Browsers.
The primary function of XSL is to transform XML documents. The XSL language features a set of programming constructs that support this function
http://www.princexml.com/howcome/2007/xtech/papers/output/0082-32/index.xhtml
XSL Sample
<?xml version="1.0" encoding="UTF-8"?><xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html"/><xsl:template match="/dc">
Processing Instructions</xsl:template>
</xsl:stylesheet>
Contents of <xsl:template...><html>
<head><title>Sample XSL transformation</title>
</head><body>
<xsl:for-each select="*"><p>
<b><xsl:value-of select="name(.)"/><xsl:text>:</xsl:text>
</b><xsl:value-of select="./text()"/>
</p></xsl:for-each>
</body></html>
XSL – Sample Stylesheet<?xml version="1.0" encoding="UTF-8"?><xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/rss"><html>
<body><xsl:for-each select="./channel/item">
<xsl:value-of select="title"/><br/></xsl:for-each>
</body></html>
</xsl:template></xsl:stylesheet>
XML RSS Record
<?xml version="1.0"?> <rss version="2.0">
<channel> <title>Sample RSS File</title><link>http://urltofile.xml</link> <description>This is a sample</description> <language>en-us</language> <pubDate>Tue, 10 Jun 2003 04:00:00 GMT</pubDate> <item>…</item><item>…</item><item>…</item><item>…</item>
</channel></rss>
WorkTime!
• Get into groups and work through our XSL worksheet.
• Ask questions• Pause for discussion
XSL Control Structures
• For Each• <xsl:for-each select=“/date”></xsl:for-each>
• Choosing between options• <xsl:choose>
– <xsl:when select=“contains(/URL, “.edu”)>– </xsl:when>
• </xsl:choose>
• If• <xsl:if test=“./title != ‘’> </xsl:if>
XPath
• A DOM-style syntax that allows us to access elements in an XML file
• Examples– /dublinCore/title
– Access the title of a DC record
– /dulinCore/subject/@attribute– Access an attribute of the subject element
– /dublinCore/
Xpath (2)
• Xpath functions– Contains (//item/title, ‘England’)– substring-before(string1, string2), substring-
after(string1, string2)
• Xpath selectors– //elementname – finds an element anywhere in the
DOM– ./ - from the current context– / - from the root context– * - wildcard match
Wrap-up
• Questions about Assignment 2?• Next week – Classification!
• Course feedback: – http://bit.ly/lbsc670_questions