<!ATTLIST element_name attribute_name attribute_type “default_value”> 

Element_name
. The name of the element that has the attribute.
Attribute_name.
The name of the attribute.
Attribute_type.
The kind of attribute. The most common attribute type is CDATA. A CDATA attribute is character data.
Default_value.
The value of the attribute if no attribute value occurs in the XML file.
Use the following options with a default value:
#REQUIRED.
The XML file must contain the attribute value.
#IMPLIED.
The attribute value is optional.
#FIXED.
The XML file must contain the default value from the DTD file. A valid XML file can contain the same attribute value as the DTD, or the XML file can have no attribute value. You must specify a default value with this option.
The following example shows an attribute with a fixed value:
<!ATTLIST product product_name CDATA #FIXED “vacuum”>
The element name is product. The attribute is product_name. The attribute has a default value, vacuum.