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Published byScot Martin Modified over 9 years ago
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Transforming XML Part I Document Navigation with XPath John Arnett, MSc Standards Modeller Information and Statistics Division NHSScotland Tel: 0131 551 8073 (x2073) mailto:John.Arnett@isd.csa.scot.nhs.uk http://isdscotland.org/xml
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Contents Document Processing Nodes and Trees XPath: Locating Nodes Summary Find Out More
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Document Processing The XSL Family –XPath (XML Path Language) –XSLT (Extensible Stylesheet Language Transformations) –XSL aka XSL-FO (Extensible Stylesheet Language Formatting Objects)
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Document Processing XPath –Used to locate specific parts of an XML source document efficiently and effectively –XPath v1.0 W3C Recommendation
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Document Processing XSLT –Used to transform XML documents to another XML or non-XML form – esp. HTML –XSLT v1.0 W3C Recommendation v2.0 W3C Working Draft –Uses XPath for locating document content
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Document Processing XSL(-FO) –Used to format XML documents into fixed sized folios for publication –XSL v1.0 W3C Recommendation –Uses XSLT for document transformation
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Document Processing Transformation and formatting –XPath used to locate nodes for input –XSLT used to transform input and generate result tree –XSL-FO used to format output document
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Document Processing Adapted from XSLT Basics slide presentation by Paul Spencer, alphaXML Source Tree Style sheet FormatTransform Result Tree Formatted Output Stylesheet Processor
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Trees and Nodes XML document is viewed as a source tree containing different node types –root –element –text –attribute –namespace –processing instruction –comment
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Trees and Nodes XML Appointment example John Smith 0141 662 2673 Alison Young 14:30:00
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Trees and Nodes XPath view of Appointment source tree
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XPath: Locating Nodes XPath expressions (location paths) –Used to navigate source tree and locate nodes for input –Comprised of one or more location steps axis + node test + (optional) predicate –May contain functions, e.g. position(), count(node-set), last()
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XPath: Locating Nodes Axes –Specify node locations relative to the current (context) node = self –May traverse tree forwards or backwards
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XPath: Locating Nodes Axes for forward traversal –child –attribute –descendant-or-self –descendant –following –following-sibling –namespace
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XPath: Locating Nodes Axes for reverse traversal –parent –ancestor –ancestor-or-self –preceding –preceding-sibling
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XPath: Locating Nodes Node Tests –Refine node set selection * = select all nodes of same type node() = select all nodes of any type Select all nodes of type text(), comment() or processing- instruction() Select all nodes with specified name
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XPath: Locating Nodes Select Clinician element node child::Appointment/child::Clinician or Appointment/Clinician
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XPath: Locating Nodes Select upi attribute node child::Patient/attribute::upi or Patient/@upi
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XPath: Locating Nodes Select all descendant text nodes /descendant-or-self::node()/child::text() or //text()
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XPath: Locating Nodes Select parent of StartTime element parent::node() or..
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XPath: Locating Nodes Using wildcards child::* or *
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XPath: Locating Nodes Abbreviating location steps –child:: and text() can usually be omitted child::Appointment/child::Clinician/child ::text() = Appointment/Clinician –attribute:: = @ Patient/@upi –self()::node =. –parent::node() =..
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XPath: Locating Nodes Abbreviating Location Paths /descendant-or-self::node()/ = // /descendant-or-self::node()/child::text() = //text()
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In Summary… XML document processing: –XPath - node location –XSLT - transformation –XSL-(FO) - document formatting XPath used to navigate source tree Transformation performed by applying style sheet to source document
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Find Out More The Extensible Stylesheet Language Family (XSL) –www.w3.org/Style/XSL/www.w3.org/Style/XSL/ W3C XML Path Language v1.0 Specification –www.w3.org/TR/xpathwww.w3.org/TR/xpath TopXML XSLT & XPath Tutorial –www.vbxml.com/xsl/tutorials/intro/d efault.aspwww.vbxml.com/xsl/tutorials/intro/d efault.asp
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