XML Primer

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XML Primer
Dr. Drew Hwang Computer Information Systems Cal
Poly Pomona
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What is XML?

• Extensible Markup Language
• A markup language and a language for creating
  markup language
• Use customized tags to describe and manage data
  in specific applications
• XML document displayable in HTML
• A portable language

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XML Applications

• A replacement for EDI
• Industry-specific MXL tags
• Chemical Markup Language (CML)
• Extensible Financial Reporting Markup Language
  (XFRML)
• Synchronized Multimedia Interface Language (SMIL)
• Product Data Markup Language (PDML)
• XML Metadata Interchange Format (XMI) a
  combination of XML and UML

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XML Elements

• Case sensitive
• Quotes mandatory
• XML declaration (which version?)
• XML DTD specification (which .dtd?)
• Root element (container element)
• Sub-element (children element)
• .xml for XML .dtd for DTDs

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XML Example I

• lt?xml version "1.0"?gt
• ltarticlegt
• lttitlegtSimple XMLlt/titlegt
• ltdategt3/3/2001lt/dategt
• ltauthorgt
• ltfnamegtDrewlt/fnamegt
• ltlnamegtHwanglt/lnamegt
• lt/authorgt
• ltsummarygtXML Primerlt/summarygt
• ltcontentgtXML is a language for structuring and
  managing data. It has been used as the de facto
  protocol for extranets.
• lt/contentgt
• lt/articlegt

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XML Example II

• lt?xml version "1.0"?gt
• lt!DOCTYPE letter SYSTEM "letter.dtd"gt
• ltaddressbookgt
• ltcontact type "from"gt
• ltnamegtBill Clintonlt/namegt
• ltphonegt909-869-5289lt/phonegt
• ltcategory id "School"/gt
• lt/contactgt
• ltcontact type "to"gt
• ltnamegtGeorge Bushlt/namegt
• ltphonegt909-869-1111lt/phonegt
• ltcategory id "Work"/gt
• lt/contactgt
• lt/addressbookgt

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DTDs

• Document Type Definitions
• Define grammatical rules for conformity
• Use Extended Backus-Naur Form (EBNF) grammar for
  syntax
• Not required but recommended

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DTDs Elements

• !ELEMENT
• Specify an element
• () for one or more instances
• PCDATA for parsed character data element
• EMPTY for elements without end tag
• !ATTLIST
• Define an attribute type for an element
• IMPLIED for system-given elements
• CDATA for string attribute

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DTDs Example I

• lt!ELEMENT addressbook (contact)gt
• lt!ELEMENT contact (name, phone, category)gt
• lt!ATTLIST contact type CDATA IMPLIEDgt
• lt!ELEMENT name (PCDATA)gt
• lt!ELEMENT phone (PCDATA)gt
• lt!ELEMENT flag (EMPTY)gt
• lt!ATTLIST flag id CDATA IMPLIEDgt

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Using XML with HTML

• XML specs as data source or data island
• Use ltXMLgt tag and an ID as the parameter
• DATASRC for data source binding
• SPAN and DATAFLD for data publishing

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XML in HTML Sample I

• ltHTMLgtltBODYgt
• ltXML ID sample_xml"gt
• ltaddressbookgt
• ltcontactgt
• ltnamegtBill Clintonlt/namegt
• ltphonegt909-869-5289lt/phonegt
• lt/contactgt
• ltcontactgt
• ltnamegtGeorge Bushlt/namegt
• ltphonegt909-869-1111lt/phonegt
• lt/contactgt
• lt/addressbookgt
• lt/XMLgt

ltTABLE DATASRC"sample_xml"gt ltTHEADgtltTRgt
ltTHgtNAMElt/TDgt ltTHgtPHONElt/TDgt
lt/TRgtlt/THEADgt ltTRgt ltTDgtltSPAN DATAFLD
name"gtlt/SPANgtlt/TDgt ltTDgtltSPAN DATAFLD
phone"gtlt/SPANgtlt/TDgt lt/TRgt lt/TABLEgt lt/BODYgtlt/HT
MLgt
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XML Parser
XML Document
XML Parser
XML Application
XML DTD (optional)