A Rule allows defining an entity member as the result of a formula based on other members of the same entity. Rules are sets of formulas defined on members of the same entity. A Rule is associated to an entity and can be used with (or applied to) all InfoCubes structured by that entity.
A typical example is that of a profit & loss statement (P&L) where some P&L lines are calculated from other lines. Consider the P&L as being an entity in which the P&L lines are its members (as follows):
L01 Gross Sales
L02 Cost of goods sold
L03 Gross Margin
L04 % on GS
L05 Distribution costs
L06 Inventory
L07 Total distribution costs
L08 % on Gross Income
L09 marketing costs
L10 advertising
L11 total mktg costs
L12 %
L13 R&D
L14 IT costs
L15 Gen & Admin
L16 Other Operating Expenses
L17 Total Operating Expenses
L18 %
L23 Net Operating Income
Some lines are calculated from other lines, for example:
L03 Gross margin = Gross Sales – Cost of goods sold
L02 % on GS = Gross Income / Gross Sales * 100
L05 Total Distrib costs = Distribution costs + Inventory
L08 % on Gross Income = Total Distrib costs / Gross income * 100