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XML Elements vs. Attributes

WebProgrammer — Sat, 19 Jun 2010 09:06:11 +0000

Elements vs. Attributes in XML

Data can be stored in child elements or in attributes.
Take a look at these examples:
< person sex="female" >
< firstname>Anna
< lastname>Smith
< /person >
< person >
< sex >female< /sex >
< firstname >Anna< /firstname >
< lastname >Smith< /lastname >
< /person >
• In the first example sex is an attribute. In the last, sex is a child element. Both examples provide the same information.
• There are no rules about when to use attributes, and when to use child elements.. Use child elements if the information feels like data.

XML Attributes

XML elements can have attributes.
• From HTML you will remember this: . The SRC attribute provides additional information about the IMG element.
• In HTML (and in XML) attributes provide additional information about elements:

XML Element Naming

WebProgrammer — Sat, 19 Jun 2010 08:25:47 +0000

Here’s the brief desription about the Element Naming.

• XML elements must follow these naming rules:

• Names can contain letters, numbers, and other characters

• Names must not start with a number or punctuation character

• Names must not start with the letters xml (or XML or Xml ..)

• Names cannot contain spaces
XML Elements are Extensible

XML documents can be extended to carry more information.
Look at the following XML NOTE example:

Tove

Jani

Don’t forget me this weekend!

XML Elements have Relationships

Elements are related as parents and children.

Example

Introduction to XML

What is HTML What is XML

XML Syntax

Closing tag properly nested

XML Elements

• XML Elements are extensible and they have relationships.

• XML Elements have simple naming rules.
Comments in XML

• The syntax for writing comments in XML is similar to that of HTML.

XML Attributes

WebProgrammer — Thu, 17 Jun 2010 13:33:04 +0000

XML Attribute values must always be quoted

• With XML, it is illegal to omit quotation marks around attribute values.
• XML elements can have attributes in name/value pairs just like in HTML. In XML the attribute value must always be quoted.

Tove
Jani

With XML, white space is preserved

• With XML, the white space in your document is not truncated.
This is unlike HTML. With HTML, a sentence like this:
Hello my name is Tove,
will be displayed like this:
Hello my name is Tove,
• HTML reduces multiple, consecutive white space characters to a single white space.

XML tags

WebProgrammer — Wed, 16 Jun 2010 13:40:53 +0000

Let us take look of how XML tags are case sensitive.

• Unlike HTML, XML tags are case sensitive.

• With XML, the tag is different from the tag .

• Opening and closing tags must therefore be written with the same case:

• This is incorrect

• This is correct

All XML elements must be properly nested

Improper nesting of tags makes no sense to XML.
In HTML some elements can be improperly nested within each other like this:
This text is bold and italic
In XML all elements must be properly nested within each other like this:
This text is bold and italic

All XML documents must have a root element

• All XML documents must contain a single tag pair to define a root element.

• All other elements must be within this root element.

• All elements can have sub elements (child elements). Sub elements must be correctly nested within their parent element:

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