<:?XML version="1.0" encoding="iso-8859-1" ?>: |
This is the first line in the file. It identifies the version
of the XML specification used. |
<:!-- Comment -->: |
Comments inside the file. |
<:!ELEMENT ElementName (SubElement1?, SubElement2*, SubElement3+)>: |
This is how to define an element named "ElementName", which
is composed of three types of elements named SubElement1, SubElement2,
and SubElement3. These elements must also be defined in the file as
ELEMENT entries. The symbol immediately after the element names indicates
the multiplicity of the relationship; that is, how many sub-elements
an element contains: - ? means 0 or 1
- * means 0 or more
- + means 1 or more
If no symbol is found, the element has one, and only one, sub-element. |
<:!ELEMENT ElementName EMPTY>: |
An element with no sub-elements. |
<:!ATTLIST ElementName attribute1 CDATA #IMPLIED attribute2
CDATA #REQUIRED attributeN CDATA "default value">: |
This is the way to define a set of attributes for an element
named "ElementName". This example shows that attributes can be defined
as either mandatory (#REQUIRED) or optional (#IMPLIED), based on whether
they must be present in the definition of the element in the XML file.
The last line, with a value included in double quotes, shows how a
default value can be set for an attribute. |