There are five time hierarchies: calendar, business, fiscal, advertising, and planning. The top level of each is a year entity, the bottom entityin each hierarchy is Day which is also within Weekday and Calendar Week. The calendar hierarchy is: Calendar Year, Calendar Half Year, Calendar Quarter, Calendar Month, Calendar Half Month, Day. The business hierarchy is: Business Year, Business Half Year, Business Quarter, Business Month, Business Half Month, Business Week, Day. The fiscal hierarchy is: Fiscal Year, Fiscal Half Year, Fiscal Quarter, Fiscal Month, Fiscal Half Month, Fiscal Week, Day. The advertising hierarchy is: Advertising Year, Advertising Quarter, Advertising Period, Advertising Week, Day. The planning hierarchy is: Planning Year, Planning Quarter, Planning Period, Planning Week, Day.