Introduction to the Logical Structure of XML Documents

1
Introduction to the Logical Structure of XML
Documents

• Web Engineering, SS 2007
• Tomáš Pitner, Michael Derntl

2
Example of an XML Document

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

3
XML Document Prolog/Heading

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Version typically 1.0
Character encoding UTF-8, UTF-16, US-ASCII
always work!
XML Prolog
4
XML Document - Root Element

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Root element contains most of the information in
the doc, every doc must have exactly one root
element!
5
Elements and Tags
Element
Element Name

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Start Tag of the element
End Tag of the element
6
Attributes
Attribute placed in the element's start tag

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Attribute Value in single or double quotes!
Note multiple Attributes are separated through
whitespace
Attribute Name unique within an element!
7
Element Content Text Nodes

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Element
Element Content Text Node
8
Element Content Child Elements
(Parent) Element

• lt?xml version'1.0' encoding'UTF-8'?gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Element Content Child Elements
9
XML Document with DTD

• lt?xml version'1.0' encoding'UTF-8'?gt
• lt!DOCTYPE staff SYSTEM "staff.dtd"gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Root element name
System identifier (URI) of the entity/file with
Document Type Definition
Document Type Declaration
10
XML Document with Comment

• lt?xml version'1.0' encoding'UTF-8'?gt
• lt!-- Comment content --gt
• lt!DOCTYPE staff SYSTEM "staff.dtd"gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

Comment content
Comment (-node) usually not interpreted by the
application
11
Processing Instructions

• lt?xml version'1.0' encoding'UTF-8'?gt
• lt?xml-stylesheet href"style.css"
  type"text/css"?gt
• lt!DOCTYPE staff SYSTEM "staff.dtd"gt
• ltstaff organization"Bundesregierung"gt
• ltperson id"agu"gt
• ltnamegtAlfred Gusenbauerlt/namegt
• ltparty url"http//www.spoe.at"gtSPÖlt/partygt
• lt/persongt
• ltperson id"wmo"gt
• ltnamegtWilhelm Moltererlt/namegt
• ltparty url"http//www.oevp.at"gtÖVPlt/partygt
• lt/persongt
• lt/staffgt

PI Target
PI Data (no attributes!)
Processing Instruction interpretation depends on
application