XML Schema choice element allows only one of the elements contained in the <choice> declaration to be present within the containing element.
(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 choice element)
|id||Optional. Specifies a unique ID for the element|
|maxOccurs||Optional. Specifies the maximum number of times the choice element can occur in the parent element. The value can be any number >= 0, or if you want to set no limit on the maximum number, use the value "unbounded". Default value is 1|
|minOccurs||Optional. Specifies the minimum number of times the choice element can occur in the parent the element. The value can be any number >= 0. Default value is 1|
|any attributes||Optional. Specifies any other attributes with non-schema namespace|
The example above defines an element named "person" which must contain either a "employee" element or a "member" element.