Essbase provides a suite of functions and calculation operators to facilitate the definition and application of complex member formulas.

Many Essbase functions identify a member in the cube by its position in the outline. The outline structure represents a hierarchical tree; every dimension represents a subsection of the tree. Generations and levels provide position references for all members within the tree. Position references are required because many applications must be able to determine the location of members within the hierarchy.

The terms "generation" and "level" denote the distance from either the "root" or the "leaves" of the dimension. Thus, you can determine the location of any member within a hierarchy. You can also specify relationships between groups of related members.

Generations specify the distance of members from the root of their dimension. All members that are the same number of branches from their root have the same generation number. The dimension is generation 1, its children are generation 2, and so on.

Levels measure the number of branches between a member and the lowest member below it, that is, the number of branches between a member and the "leaf" of its hierarchy within the outline structure. Level 0 specifies the bottom-most members of a dimension and thus provides ready access to the raw data stored in the cube. Leaf members are level 0, then their parents are level 1, and so on up the hierarchy.

You might note that when all sibling members have the same generation number but not necessarily the same level number.

For example, the members in this hierarchy:

Dim1 
 m11
  m111
  m112
 m12
  m121
  m122
 m13

have the following generation and level numbers:

Dim1    Gen 1, Level 2
 m11    Gen 2, Level 1
  m111  Gen 3, Level 0
  m112  Gen 3, Level 0
 m12    Gen 2, Level 1
  m121  Gen 3, Level 0
  m122  Gen 3, Level 0
 m13    Gen 2, Level 0

See also: Relationship Functions