id A unique ID for the element. A unique ID for the element. minOccurs 0 1 Minimum number of times the element can occur. Value can be 0 or 1. Default is 1. Minimum number of times the element can occur. Value can be 0 or 1. Default is 1. maxOccurs 1 Maximum number of times the element can occur. The value must be 1. Maximum number of times the element can occur. The value must be 1.