ISQA 407

1
ISQA 407

• Winter 2002
• Sergio Davalos, Ph.D.
• Portland State University

2
How do I link to an external Style sheet?

• See text for xsl
• What about CSS?
• lt?xmlstylesheet typetext/css
  hrefend_species.css ?gt

3
Try this

• lt?xml version 1.0?gt
• lt?xmlstylesheet typetext/css
  hrefend_species.css ?gt
• ltendangered_speciesgt
• ltintrogtThe animals and plants on our planet are
  disapp

4
ANATOMY OF AN XML DOCUMENT

• Three Segmental Structure An XML document can be
  broken up into three sections. Prolog, Root
  Element, and Epilog. An well formed and valid XML
  document (version 1) will have a "prolog" and
  root element.
• Processing Instruction The lt? xxxxx ?gt is a
  special syntax referred to as processing
  instruction. The most typical example is the XML
  declaration which indicates to the parser the
  version of XML this document would adhere to
  (lt?xml version"1.0"?gt). Processing instructions
  are information that the document would provide
  to the XML parser. What we have been following is
  the specification of XML version 1.0. In the
  future there might be additional changes to the
  XML specification that might grossly vary from
  the 1.0 recommendations. For upward compatibility
  it's a great idea to include the version of XML
  that your document adheres to. In the future we
  will see different uses for the processing
  instruction. Notice that the comment containing
  the "PROLOG" is no longer there. It's because the
  XML declaration needs to be the first information
  that the IE5 parser needs to see. The epilog can
  contain more comments and other processing
  instructions.

5
Why XML

• Obstacles to e-business
• Incompatible data formats
• Customized information exchange
• Management of distributed business data
• Inadequate internet solutions

6
Incompatible data formats

• Large number of proprietary, incompatible data
  formats
• Placing orders mail, fax, phone, voice-mail,
  on-line
• Orders have different layouts/languages
• Required information cust-id/ customer name/ref
  number
• Re-enter this to change forms?
• XML enables transmission, utilization, and
  storage of data over the Internet and across
  company boundaries

7
Customized information exchange

• Agreed upon access difficult to implement
• Different data formats
• Heterogeneous IT infratstructures
• Incompatible security systems
• Local homemade solutions
• XML enables different data types and pieces of
  information to be aligned

8
Management of distributed business data

• Large volumes of data stored in different formats
  and different locations
• Access to data restricted by the data format, OS,
  or type of DB
• XML allows setting up a system to store all
  possible data types and formats and to integrate
  data from existing external database systems and
  applications by using mapping tables and
  retrieved in a standardized manner
• Virtual DBMS

9
Inadequate internet solutions

• Companies tried to eliminate these problems with
  extensive scripting and gateway technologies
  (CGI)
• Solutions are error-prone, unreliable, difficult
  to scale, extremely complicated, and costly to
  maintain.
• Scripts usually tailored and difficult to maintain

10
Advantages of XML

• Immediately and everywhere accessible
• XML is simple and open
• Searching for data in XML databases quicker

11
Where to?

• Three-tier applications
• E-Commerce
• Integration
• Content management
• Portals
• Publishing
• Databases
• Content Acquisition