Transcript Tutorial 2: XML

Tutorial 2: XML
Working with
Namespaces
Section 2.1
COMBINING XML VOCABULARIES
IN A COMPOUND DOCUMENT
parts
+
The parts element must contain
at least one part
part
title
description
instock
The parts vocabulary includes
the title of each part, the part description, and
the number of each part currently in stock (instock)
parts.xml
parts.css
rendered Web page
model
title
description
type
ordered
parts
The model
vocabulary contains
elements for a
model’s title,
description, type, the
number of models
that need to be
assembled (ordered),
and the parts
required for the
assembly
model.css
model.xml
rendered Web page
Web page
elements
from the
XHTML
vocabulary
elements
from the
parts
vocabulary
elements
from the
model
vocabulary
model
title
description
type
ordered
parts
parts
+
part
title
description
instock
style of the model.xml content
style of the parts.xml content
style of the combined document
Rendered order.xml Web page
model
title
description
type
ordered
parts
parts
+
part
title
description
instock
Name Collision

Name collision occurs when elements from
two or more documents share the same
name.

Name collision will keep a document from
being validated.

Name collisions are often unavoidable.
Using Namespaces
to avoid Name Collision

A namespace is a defined collection of element
and attribute names.
–


For example: the model namespace and the parts
namespace
Names that belong to the same namespace
must be unique. Elements can share the same
name if they reside in different namespaces.
Namespaces must be declared before they can
be used
Working with Namespaces
Applying a namespace to an XML document
involves two steps:
1.
Declaring the namespace
2.
Identifying the elements and attributes
within the document that belong to that
namespace
Declaring a Namespace
To declare a namespace, add the following:
xmlns:prefix=“uri”
–
–
prefix is the namespace prefix and uri (used as an id)
that uniquely identifies a resource
The namespace is applied to the element containing the
xmlns attribute, as well as to its descendant elements.
Namespaces can be declared in document’s root
element
<model xmlns:mod=“http://jacksonelect.com/models”>
Applying a Namespace to Elements

After declaring the namespace, identify the elements
and attributes that belong to that namespace:
<prefix:element> . . . </prefix:element>

Examples:
<mod:title>Laser4c (pr205)</mod:title>
<mod:model
xmlns:mod=“http://jacksonelect.com/models”>
Applying the models namespace prefix
Applying the parts namespace prefix
Applying a Default Namespace

Declare a default namespace by omitting the prefix
in the namespace declaration.

<element xmlns = "uri"> ... </element>
<model xmlns = "http://jacksonelect.com/models">
<title>Laser4C (PR205)</title>
<description>Entry level color laser printer</description>
<type>color laser</type>
<ordered>320</ordered>
<parts list = "chx201,fa100-5,eng005-2,cbx-450V4,tn01-53" />
</model>
Working with Attributes

To apply a namespace to an attribute, add:
<element prefix:attribute=“value”>
Example:
<mod:model xmlns:mod=“. . ” mod:id=“pr205”>
There is no default namespace for attribute names.
An attribute name without a prefix is assumed to
belong to the namespace as the element that
contains it.
<mod:model xmlns:mod=“. . ” id=“pr205”>

Section 2.2
ADDING A NAMESPACE TO A
STYLE SHEET
Declaring a Namespace in a Style
Sheet
Add the following rule:
@namespace prefix url(uri);

Both the prefix and uri must match the prefix
and uri used in the XML document

Example: @namespace mod url(http: . . .);

Any @namespace rule must come after all
@import and @charset rules and before any
style declarations
Applying a Namespace to a Selector
prefix|selector
{attribute1:value1; attribute2:value2; . . .}
prefix\:selector

For Internet browsers
{attribute1:value1; attribute2:value2; . . .}
Examples:
–
–
–
mod|title {width: 150px}
mod|*
{font-size: 12pt}
mod\:title {width: 150px}
Applying the models namespace to the style sheet
Applying the parts namespace to the style sheet
styles applied
from the
models
namespace
styles applied
from the parts
namespace
Web page
combining
styles from
both
namespaces
Namespace URIs for standard vocabularies
Combining Standard Vocabularies

The standard vocabularies can also be combined
within single documents.

For example, Firefox, using a built-in style sheet, is
able to display the documents that combine both the
XHTML and MathML language.

The elements of almost any XML document can be
displayed in a Web browser if you design style
sheets to work with the elements of the XML
vocabulary.
XML document
with XHTML and
MathML elements
Document rendered
by Firefox
A compound XHTML and MathML document
Adding XML to an HTML document
Leave the html elements in the default namespace, and
provide namespace prefixes for all of the non-HTML
elements

Convert a HTML file into an XHTML file
–
–
adding an xml declaration
setting the default namespace of the document to the
XHTML vocabulary
<?xml version="1.0" encoding = “utf-8" standalone = "yes" ?>
<html xmlns=http://www.w3.org/1999/xhtml>
<?xml version=“1.0” encoding=“utf-8” standalone=“yes” ?>
.
<html xmlns=“http://www.w3.org/1999/xhtml”
xmlns:pa=“http://jacksonelect.com/parts”>
<head>
.
<link rel=“stylesheet” href=“parts.css” type=“text/css” />
<body>
.
<h2>Parts List</h2>
<pa:parts>
.
</pa:parts>
.
</html>
Every element that lacks a namespace prefix is
considered part of the XHTML vocabulary
Adding
descriptive text
to each of the
bulleted items
Completed
compound
report page