XML the BASICS
Extensible Markup Language
The Concept
• What is XML (Extensible Markup
Language) and what can XML do for you?
This presentation addresses that simple
question.
• Exploring the Concept
• Positioning in the Computer World
• Making a concluding statement
• <!DOCTYPE html PUBLIC “-//W3C//DTD XHMTL 1.0
• Transitional//EN” “http://www.w3.org/TR/xhtmll-transitional.dtd”>
• <html lang=”en” xml:lang=”en”
• xmlns=“http://www.w3.org/1999/xhtml”>
• <head>
• <title>Order Information - ord123456</title>
• </head>
• <body>
• <table border=”1”>
• <tr>
• <th>Artist</th>
• <th>Title</th>
• <th>Price</th>
• </tr>
• <tr>
• <td>Nelly</td>
• <td>Nellyville</td>
• <td>16.95</td>
• </tr>
• <tr>
• <td>Baby D</td>
• <td>Lil Chopper Toy</td>
• <td>17.55</td>
• <tr>
• </table>
• </body>
• </html>
• Source: (“Understanding XML”, 2006, p. 13):
Appearance in Web Browser
Artist Title Price
Nelly Nellyville 16.95
Baby D Lil Chopper
Toy
17.55
Looks Like HTML
• At a quick glance XML appears to be HTML (Hypertext
Markup Language).
• HTML is a programming language that uses tags which
are the signs < and > to enclose its language.
• XML code is also enclosed with these signs.
• HTML connects your computer’s browser with Web
servers to provide everyday readable text. XML does the
same.
• XML goes beyond HTML by incorporating its features to
work with it and extends its capability through the Web.
• XML provides meaning to what is coded whereas HTML
just provides a presentation or appearance.
XML Provides Meaning
• XML Provides Context
• So Data can be
Structured (Attributes)
• It Forms Data
Relations
• XML began as a language for defining new documents
for the World Wide Web.
• XML is derived from Standard Generalized Markup
Language (SGML) which is the father of HTML.
• Thus, XML is a markup language and is considered the
meta-language.
• According to our text metadata describes the
characteristics or properties of end user data as well as
the context for that data including its source.
• This is a starting point for extending the capability of XML.
Source: Understanding XML, 2006, pages 1 & 13.
USES
• Since XML describes metadata
• Other applications can be
integrated
• Structure data can be utilized
• Spreadsheets, network protocols
and program configuration files
• XML can represent two types of
data structures: tabular
(relational) and semi-structured
(also called unstructured).
• XML can look at a spreadsheet
application as well as the object
languages represented in a
computer program.
• XML provides a means of
describing any kind of information
(Source Morrison, 2002, p.10).
– EXTENSIBLE
• What makes XML extensible – that
which can be extended – is that it
is not tied to any programming
language, operating system or
software vendor.
INDEPENDENCE
• Platform independence makes
XML very useful as a means for
achieving interoperability between
different programming platforms
and operating systems.
– MANIPULATED
• Since XML can define data
structure, it can be manipulated
and queried to satisfy users’
needs. (Source: Morrison, 2002,
p.12).
WEB ORIENTED BUSINESS WORLD
• De Facto Standard for e-commerce
• Communicates across diverse vendors’ &
clients’ platforms
• Product catalogs, airline schedules, stock
reports, bank statements, places orders
• Other applications in Research,
academics, and the government
COMPONENTS
1. SCHEMAS
2. DOCUMENT TYPE
DECLARATIONS
(DTD)
3. COMMENTS
4. ENITY
REFERENCES
<!– This is the Rock section -->
&amp; Ampersand
&quot; Quote
&apos; Apostrophe
&lt; Less than (tag)
&gt; Greater than >
XML schemas are readily available through the sponsor of
XML, the World Wide Web Consortium (W3C).
This standards organization is working to develop open
standards for development of conventions for Web
documents that can consistently be displayed across all
platforms.
Their schema standard defines data models and
establishes data types.
Thus, they provide a custom vocabulary to describe XLM
documents. Since they have an open standard for open
computer architecture, their hyperlink can be referenced
to prescribe the XML schema. They freely provide a
recommended language to define XML databases. They
can be found at the hyperlink,
http://www.w3.org/2001/XMLSchema.
(Source: Huffier, Prescott, and McFadden, 2007, p. 396 &398)
The W3C conveys the concept of XML by
making 10 points:
1. XML is for structuring data.
2. XML looks a bit like HTML, since it uses tags (words bracketed by <
and >).
3. XML is text, but isn’t meant to be read. That means the XML code
is available for your examination but you can just read the content
contained between the code if you want. As a user you can see it in
a user’s view (a screen of plain text information) and add or modify it
to suit your needs.
4. XML is verbose by design. Since its format uses tags to delimit the
data in a text type description, XML files are larger than comparable
binary formats.
5. XLM is a family of technologies. This family is growing by offering
more modules. For example, Cascading Style Sheets (CSS) can be
used. CSS define the appearance of different elements such as
headers and links. It shapes the appearance of your document.
6. XML is new, but not that new. It is based on SGML and HTML.
7. XML leads to XHTML. This is the successor to HTML. XHMTL is a
document format developed by the W3C. More information concerning
the new technology can be found at W3C’s Web site.
8. XML is modular. Through XML schema and their convention,
namespace, modules of other formats can be combined and reused.
9. XML is the basis for Resource Description Framework (RDF) and the
Semantic Web. RDF is an XML text format that supports resource
description and metadata applications that include music and photos. It
is semantic by providing a mechanism for reaching common definitions,
an agreed meaning, which allows meaningful communications among
computer users.
10. XML is license free, platform independent and well supported. You don’t
have to pay to use it. You don’t have to pay to build on it. If you need
help, there is a growing community of tools being made available for the
technology.
• These 10 points serve as a summary of what XML is about and can start
you to specific development of a project. If you are a developer, it could
be well worthwhile your consideration.
(Source: Extensible Markup Language, 2003, www.w3.org/XML/1999/XML-in-
10-points)
CONCLUSIONS
PLUS SIDE
• Powerful markup
language
• Structures across
technology
• Adoptable to multimedia
• Object Oriented
compatible
• E-commerce de facto
standard
• Free
DRAWBACKS
• Complexity
• Open Standard
• Exposed to Web
Vulnerabilities