XML Training Course

1
XML Training Course

• Module 2 XML Syntax

2
What to expect this Session

• What is an XML Document?
• The Prolog of an XML Document
• Elements
• Attributes
• Comments
• Processing Instructions

3
Sample Document

• Joe Schmoe
• Jane Doe
• Cal Smith
• 01/31/2003
• XML Rocks
• I just returned from Montgomery where I
  attended a training session on XML provided by
  the Information Services Association. At the
  workshop I learned the basics about XML, like how
  to create an XML document and how to present it.
  I am excited to report that I have already
  brainstormed several ways we can implement XML at
  our institution that will provide better service
  to students. I look forward to meeting with you
  and sharing the knowledge and my ideas.

4
XML Document

• SGML definition a collection of information
  that is processed as a unit
• For this discussion, we will define it as the
  contents of a single file.
• That file contains tags, attributes for those
  tags, and content that goes in between the tags.

5
The Prolog (Opening Section)

• The first item that should appear in any XML
  document is the XML Declaration.
• HTML Declaration
• XML Declaration

6
XML is Case-Sensitive

• In HTML, authors have to freedom to choose how
  they write their elements.
• In XML, case does matter.
• ¹ ¹

7
The Prolog (Opening Section)

• Next come the DOCTYPE construct
• This contains the instructions about how to
  validate the document

8
The DOCTYPE Declaration

• A Document Type Definition (DTD) is a set of
  rules that validate an XML document.
• Those rules can either be written internally to
  the document or they may be referenced using a
  URL (or a combination of the two).

9
The DOCTYPE Declaration

• Made up of 3 parts
• Semantic Name (not filename) MEMO
• URL of the file http//www.foo.com/memo.dtd

10
The Document/Root Element

• Every XML document must have a single element
  that contains all other elements.
• This is known as the Root Element or the Document
  Element.
• In our example is the root element.

11
Document Content

• What comes next is what we traditionally think of
  as the the document that is, the actual
  content.
• Expressed using one of 4 methods
• Elements
• Attributes
• Comments
• Processing Instructions

12
Elements

• Elements are the primary logical components of a
  document.
• They are bound by start tags and end tags.
• Hostess Twinkies

13
Elements

• Sometimes elements do not have any content.
  These are known as empty elements.
• 
  
• XML requires all elements be complete
• 
  
  
• or
• 
  

14
Attributes

• A property of an element
• Expressed as information within the elements
  start tag
• Hostess Twinkies

15
Attributes

• Composed structurally of name value pairs
• All attributes values must be enclosed in
  quotation marks.
• Guideline Use attributes to store information
  about the element.

16
Comments

• A comment written in XML is syntactically
  equivalent to those found in HTML.
• Comments may appear anywhere in a document,
  provided they are outside other markup and not
  immediately prior to the XML Declaration.

17
Processing Instructions

• Markup that provides information to be used by
  software applications.
• The first entry after the refers to the application for which the
  instruction is intended.
• The second entry tells the application exactly
  what to do.

18
Rules Review

• All tags must be properly terminated with an end
  tag, like this .
• Tag names are case-sensitive. The following would
  generate an error .
• Empty tags may be defined as well and can be
  expressed in one of two ways or
  .
• Tag data should always be enclosed in matching
  single or double quotes.
• The construct of tag, data, and end tag is
  referred to as an element.
• An element may contain other elements, as long as
  the end tags of the contained elements come
  before the end tag of the containing element.
• Every XML document must have only one root
  element that contains all other elements in the
  document.
• Comments are ignored by the parser and are
  enclosed in comment tags .

19
Review this Session

• What is an XML Document?
• The Prolog of an XML Document
• Elements
• Attributes
• Comments
• Processing Instructions

20
Build a Complete XML Document

• You have been given a menu for a menu for a cafe.
  Create an XML document that represents that menu.