In generall, a hierarchy is a collection of levels based on attributes. With that said, there are existing natural hierarchies, like country, state and city1) as well as year, month, week, and day also known as time hierarchy2) . These two examples represents a natural relationship 3) related to attributes. By that, its important to know, that a natural hierarchy has only one parent and also implies the member attribute above it. 4) In this connection there is an opportunity to create more individual hierarchies also referred to as user-defined-hierarchy.