The BooleanConstantEnumType enumerates values of the two Boolean constants. (The names are of these enumerated values are chosen to avoid conflicts with reserved words and macro definitions in common computer languages.)
<xs:simpleType name="BooleanConstantEnumType"><xs:annotation><xs:documentation>The BooleanConstantEnumType enumerates values of the two Boolean constants. (The names are of these enumerated values are chosen to avoid conflicts with reserved words and macro definitions in common computer languages.)</xs:documentation></xs:annotation><xs:restriction base="xs:NMTOKEN"><xs:enumeration value="QIF_TRUE"/><xs:enumeration value="QIF_FALSE"/></xs:restriction></xs:simpleType>