XML Extensible Markup Language

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XML (Extensible Markup Language)
Prepared by Jaclyn Soh
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XML (Extensible Markup Language)

• a language for describing structured data.
• improves on the HTML approach makes the web a
  better place in which to do a business, to learn,
  and to have fun.
• have a freedom to use pretty much any names you
  like to tag up your data.

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Example
lt!-- HTML Snippet --gt lth1gtInvoicelt/h1gt ltpgtFrom
Jaclyn Soh ltpgtTo Whoever ltpgtAmount
100.00 ltpgtTax 21 ltpgtTotal Due 121.00 View in
.html
lt!-- XML Snippet --gt ltInvoicegt ltFromgtJaclyn
Sohlt/Fromgt ltTogtWhoeverlt/Togt ltDategtYear2001
month4 day16/gt ltAmount
currency Dollarsgt100.00 lt/Amountgt ltTaxRategt21lt
/TaxRategt ltTotalDue currency Dollarsgt121.00 lt/
TotalDuegt lt/Invoicegt View in .xml from
.xml to .html
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XML Cont.

• any language based on XML consists of a set of
  element types that have been given certain names
  certain meanings.
• the presence of elements of various types in
  documents is indicated by tags that serve to
  indicate where the element starts and ends.
• a set of element types serves to define types of
  documents and are referred to as Document Type
  Definitions, or DTD.

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XSL Extensible Stylesheet Language

• Extensible Stylesheet Language (XSL)
• relationship between XML and XSL is similar to
  the relationship between HTML and CSS.
• example

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More XML

• strictly hierarchical.
• can have only one root element.
• Example ltInvoicegt document, the ltInvoicegt
  element is called root element.
• root element is the top-level element in the
  document, and all the other elements are its
  children or descendents.

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XML Generosity???

• indeed! XML is very generous in the names were
  allowed to use.
• For example, there arent any reserved words to
  avoid in XML, as there are in most programming
  languages. We have a lot flexibility in this
  regard.
• However

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• Some rules to follows
• names can start with letters (including
  non-Latin characters) or the _ character, but
  not numbers or other punctuation characters.
• after the first character, numbers are allowed,
  as are the characters _ and ..
• names cant contain spaces.
• names cant contain the character.
• names cant start with letters xml, in
  uppercase, lowercase, or mixed.
• there cant be a space after the opening lt
  character the name of the element must come
  immediately after it.
• case sensitive.
• For example, ltfirstgt is different from ltFIRSTgt

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Questions

• XML is used for describing structural data. (T/F)
• XML document can have more than one root element.
  (T/F)
• XML is not case sensitive. (T/F)
• XML allows you to create your own tags to
  precisely describe data. (T/F)
• Names can start with letters, characters, numbers
  and punctuation. (T/F)