DayTypeAssignment

We currently use DayType to store the national holidays.

Table: DayTypeAssignment

Sub	Element	Usage	Card	Type	Description	Note
	@id	mandatory	1..1	xsd:string	Attribute id
	@version	mandatory	1..1	xsd:string	Attribute version
	Date	mandatory	0..1	xsd:date	Calendar date of assignment.
	DayTypeRef	mandatory	1..*	DayTypeRefStructure	Reference to a DAY TYPE.