The attributeGroup element is used to group a set of attribute declarations so that they can be incorporated as a group into complex type definitions.
(The ? sign declares that the element can occur zero or one time, and the * sign declares that the element can occur zero or more times inside the attributeGroup element)
|id||Optional. Specifies a unique ID for the element|
|name||Optional. Specifies the name of the attribute group. Name and ref attributes cannot both be present|
|ref||Optional. Specifies a reference to a named attribute group. Name and ref attributes cannot both be present|
|any attributes||Optional. Specifies any other attributes with non-schema namespace|
The example above defines an attribute group named "personattr" which is used in a complex type named "person".