Xml

•XML stands for EXtensible Markup Language
•XML is a markup language much like HTML
•XML was designed to carry data, not to display data
•XML tags are not predefined. You must define your own tags
•XML is designed to be self-descriptive
•XML is a W3C Recommendation

There are two current versions of XML. The first XML 1.0 was initially defined in
1998 and it has undergone minor changes/revisions since then. Though changes
have been done, a new revision number has not been assigned to this version. It is
called XML 1.0 5th edition, with the latest edition (5th) being released on 26th Nov
2008.

The second version XML 1.1 was initially published on 4th Feb 2004, the same day
as the XML 1.0, 3rd edition. XML 1.1 is currently in its 2nd edition which was
released on 16th Aug 2006. It contains certain features that are expected to make
XML easier to use.

.

Mobile Application Web Services

Windows Application

Web Application

XML

DB2 Oracle
SQL Server Access
Data Sources

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Domain-specific vocabulary
Data interchange
Smart searches
Granular updates
User-selected view of data
Message transformation

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The various components of an XML
document used for representing data in a
hierarchical order are:
Processing Instruction (PI)
Tags
Elements
Content
Attributes
Entities
Comments

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<?xml version=“1.0” encoding=“UTF-8”?>
<STOREDATA> Processing Instruction (PI)
 Provides information on how
<STORE STOREID=“S101”> the XML file should be
<PRODUCTNAME>Toys</PRODUCTNAME> processed.

<QUANTITY>100</QUANTITY>
<DISPLAY>The price of this toy
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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<STOREDATA>
 Tags
<STORE STOREID=“S101”> Is a means of identifying
<PRODUCTNAME>Toys</PRODUCTNAME> data. Tags consist of start
tag and end tag.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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<STOREDATA>
Root Element

<STORE STOREID=“S101”> Contains all other elements
<PRODUCTNAME>Toys</PRODUCTNAME> in the document.

is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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<STOREDATA>
Comments
<STORE STOREID=“S101”>
<PRODUCTNAME>Toys</PRODUCTNAME> Are statements used to
explain the XML code.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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<STOREDATA>
Child Elements
<PRODUCTNAME>Toys</PRODUCTNAME>
Are the basic units used to
<QUANTITY>100</QUANTITY> identify and describe data in
XML.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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Components of an XML Document (Contd.)

<STOREDATA>
<PRODUCTNAME>Toys</PRODUCTNAME> Attributes
Provide additional
<QUANTITY>100</QUANTITY> information about the
<DISPLAY>The price of this toy elements for which they are
declared.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

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<STOREDATA>
<PRODUCTNAME>Toys</PRODUCTNAME> Content

<QUANTITY>100</QUANTITY> Refers to the information
represented by the elements
<DISPLAY>The price of this toy of an XML document. An
is < 200 </DISPLAY> element can contain:
</STORE>
• Character or data content
</STOREDATA>
• Element content
• Combination or mixed
content

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<STOREDATA>
<PRODUCTNAME>Toys</PRODUCTNAME>

<QUANTITY>100</QUANTITY> Entities
<DISPLAY>The price of this toy Is a set of information that
is < 200 </DISPLAY> can be used by specifying a
</STORE> single name.
</STOREDATA>

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Every start tag must have an end tag.
Empty tags must be closed using a forward
slash (/).
All attribute values must be given in double
quotation marks.
Tags must have proper nesting.
XML tags are case sensitive.

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Element declaration

Syntax
<!ELEMENT element-name (element-content)>
Example
<!ELEMENT employee(#PCDATA)>

Any Element content
<!ELEMENT employee ANY>
Other Child Element as Content
<!ELEMENT employee (name,phone,age,dept)>
At least One occurrence of child element
<!ELEMENT employee (name,contact+)>
Zero or more occurrence of element
<!ELEMENT employee(name,phone,email*)>

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Attribute Declaration

Syntax
<!ATTLIST element-name attribute-name attribute-type default-value>

Example
<!ATTLIST payment type CDATA "check">

Entities
Entity References Character
< <
> >
& &
" "
' '


<?xml version="1.0"?>
<!DOCTYPE note [
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>
]>

<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend</body>
</note>

http://www.xmlvalidation.com/


Note.dtd
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>

Referring DTD from XML
<!DOCTYPE root-element SYSTEM "filename">
Note.xml
<?xml version="1.0"?>
<!DOCTYPE note SYSTEM "note.dtd">
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!
</body>
</note>

An XML schema defines the list of
elements and attributes that can be
used in an XML document.
An XML schema specifies the order in
which the elements appear in the XML
document, and their data types.
Microsoft has developed the XML
Schema Definition (XSD) language to
define the schema of an XML
document.

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Some of the advantages of creating an XML
schema by using XSD are:
XSD provides control over the type of data that can
be assigned to elements and attributes.
XSD enables you to create your own data types.
XSD enables you to specify restrictions on data.
The syntax for defining an XSD is the same as the
syntax used for XML documents.
XML schema content models can be used to
validate mixed content.
XML schema is extensible.
XML schema is self documenting.

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Data Types in XML Schemas (Contd.)

In an XML schema created using
XSD, every element must be
associated with a data type.
XSD Data Types
Primitive
User Defined
Simple Type
Complex Type

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A Boolean true or false value. Representations of true are "true" and "1"; false
is denoted as "false" or "0".
boolean

byte A signed 8-bit integer in the range [-128, 127].
date Represents a specific date
Represents a specific instant of time. It has the form YYYY-MM-DDThh:mm:ss
dateTime
folowed by an optional time-zone suffix
decimal Any base-10 fixed-point number.
double A 64-bit floating-point decimal number
float A 32-bit floating-point decimal number
int
Represents a 32-bit signed integer in the range [-2,147,483,648, 2,147,483,647].
integer Represents a signed integer
language One of the standardized language codes
long A signed, extended-precision integer; at least 18 digits are guaranteed
negativeInteger Represents an integer less than zero
nonNegativeInteger An integer greater than or equal to zero
nonPositiveInteger An integer less than or equal to zero.
positiveInteger An extended-precision integer greater than zero
string Any sequence of zero or more characters.

1. Complex Type : A data type which contains other elements.
2. Simple Type : A data type which contains one formatted element.

A CSS is a text file containing one or
more rules or definitions for the style
characteristics of a particular
element.
It controls how tags are formatted in
XML and HTML documents.
The CSS file can be included in XML
documents with the same data
structure.

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A CSS can be applied to an XML
document using the following
syntax: Specifies the type of
<?xml:stylesheet type="text/css" formatting that is being used.
href="path-name"?>

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Introducing XSL

CSS does not support the reorder, sort, and display of
elements based on a condition.
For such advanced formatting, XML supports
Extensible Style Sheet Language (XSL).
XSL has two parts:
XSL Transformations (XSLT)
XML Path (XPath)
XSL:
Contains instructions on how an XML document should
be transformed into an HTML or an XHTML document.
Uses XPath expressions to extract specific data from an
XML document.
The XSLT processor transforms the XML document
into an HTML or XHTML or into another XML
document.

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The XSLT processor applies the
transformation information to the
source document and builds the
result tree as shown in the following
figure. MSXML Parser

XSLT style sheet XSLT tree

XSLT Result tree
processor

XML document Source tree

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XSLT provides the following
elements to select and format data:
stylesheet
value-of
for-each
sort
text

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c stylesheet Instructs the browser that the document is a style
sheet file.
g value-of Is the root element for all XSLT style sheets.
Is written as:
g for-each <xsl:stylesheet
xmlns:xsl=

g sort "http://www.w3.org/1999/XSL/Transform"
version="1.0">

g text

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Displays the value of the specified element or
c stylesheet attribute.
Follows the syntax:
g value-of <xsl:value‑of
select="elementname/attributename"/>
g for-each
g sort
g text

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c stylesheet Instructs the XSLT processor to process the
information for each instance of the specified pattern.
g value-of Follows the syntax:
<xsl:for-each select="pattern">
g for-each [action to be performed]
</xsl:for-each>
g sort
g text

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c stylesheet
g value-of Sorts data based on the values assigned to elements
and
g for-each attributes.
Follows the syntax:
<xsl:sort select="expression"
g sort order="ascending | descending"
case-order="upper-first | lower-first“
g text data-type="text | number | qname"/>

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c stylesheet
g value-of
Generates constant text in the output and displays
g for-each labels.
Follows the syntax:
g sort <xsl:text> Text to be displayed as
label </xsl:text>
g text

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Used with the if and choose elements to narrow down
the formatting criteria.
r The following table lists various comparison and Boolean
operators.
Operator Meaning Example
PRICE[. = 20]
= Equal to PRODUCTNAME[. = ‘Mini Bus’]
PRICE[. != 20]
!= Not equal to
PRODUCTNAME[. != ‘Barbie Doll’]
< Less than PRICE[. < 20]
> Greater than PRICE[. > 20]
<= Less than or equal to PRICE[. <= 20]
>= Greater than or equal to PRICE[. >= 20]
and Logical AND PRICE[. &gt 20 and . < 30]

or Logical OR PRICE[. = 20 or . = 45]
not Negation operator PRICE[not(. = 30)]

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Operator/Special Example Description
Character

@ @PRODUCTID Used as a prefix for the attribute.

@* @* Selects all attributes.

: : Separates the namespace prefix from the element or
attribute name.

( ) (PRICE*QUANTITY) Used to group operations.

[ ] [@PRODUCTID='P001'] Applies a filter pattern.

+ num1 + num2 Returns the sum of two numbers.

- num1 - num2 Returns the difference of two numbers.

* num1 * num2 Returns the product of two numbers.

div num1 div num2 Returns the quotient of two numbers.

mod num1 mod num2 Returns the modulus, that is, the remainder of integer
division.

DOM defines the logical structure of documents.
DOM provides an Application Programming Interface
(API) for dynamically accessing and manipulating a
document.
The DOM objects have associated methods and
properties to access and manipulate a document.
A DOM-enabled parser is required to use the features
provided by DOM.
A DOM-enabled parser:
Parses an XML document to ascertain its validity.
Creates an in‑memory representation of the XML
document as a tree structure.

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MSXML parser:
Is the Microsoft implementation of DOM.
Provides fundamental as well as added interfaces to access
documents.
The following figure represents how a DOM tree is used by
applications to access data.

MSXML Library

XML DOM Tree
Document Parser Root Application
Parsed Child
Document Text
Child
Text

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Following are the key DOM objects:
Document
Element
Node
NodeList
Attr
Text
ParseError

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Following are the the top-level object thatobjects:
•It is
key DOM implements all the
basic DOM methods.
e Document •It also has methods that support XSLT.
•It has methods that can be used to navigate,
e Element query, and modify the content and structure of
an XML document.
•Some of the methods provided by this object
e Node are createElement(), createAttribute(),
createComment() , and createTextNode().
e NodeList •Some of the properties provided by this object that
help in manipulating the information contained in
e Attr the object are async, childNodes, firstChild,
documentElement, xml, and readyState.

e Text
e ParseError

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e Document •It represents all the element nodes in an XML
document.
e Element •The attributes associated with the elements are

considered to be the properties of the elements
e Node rather than their child elements.
•Some of the methods of this object are
e NodeList also inherited from the Node object.
•Some of the methods provided by this object
are
e Attr getAttribute(),
getElementsByTagName(),
e Text normalize(), and removeAttributeNS().

e ParseError

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e Document
It represents a single node in the XML document
e Element tree structure.
It provides methods to work with child elements.
e Node Some of the methods of this object are
appendChild(newChild),
insertBefore(newNode,refNode),
e NodeList and removeChild(nodeName).

e Attr
e Text
e ParseError

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e Document
e Element  It provides a list of nodes present in an XML
document for manipulation.
e Node  This object enables you to iterate through a
collection of nodes.
e NodeList  Some of the method of this object are item()
and nextNode().

e Attr
e Text
e ParseError

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e Document
e Element
e Node It represents an attribute of the Element
object.
It is also a Node and inherits various
e NodeList attributes
and methods of Node object.
e Attr An attribute is not considered by the DOM to
be
e Text a child node of an element, but rather a property.

e ParseError

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e Document
e Element
e Node
It represents the text inside an XML element
in
e NodeList the node tree.
The splitText() method is associated
e Attr with
this object.

e Text
e ParseError

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XML DOM Objects in Scripts

The DOM objects can be used within
scripting languages such as
JavaScript and VBScript.
Using DOM objects in scripts allow
dynamically applying a style sheet to
an XML document.
The code for using DOM objects for
accessing an XML document needs
to be used as an HTML page.

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04/05/12 50

Xml

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