Default and Fixed Values
Attributes can have default values. To specify a default value, use the
default attribute of the
xs:attribute element. Default values for attributes work slightly differently than they do for elements. If the attribute is not included in the instance document, the schema processor inserts it with the default value. You may test Attributes/Demos/NatHawthorne2.xml against this schema.
Attribute values can be fixed, meaning that, if they appear in the instance document, they must contain a specified value. Like with simple-type elements, this is done with the fixed attribute. You may test Attributes/Demos/NatHawthorne3.xml against this schema.