Dimension 

Definition

The grouping of classification groups (characteristics) whose content is logically connected, under a single generic term. If the dimension contains a characteristic whose value already uniquely determines the values of all other characteristics from a business-orientated viewpoint, then the dimension is named after this characteristic.

                                                                

The customer dimension could, for example, be made up of the customer number, the customer group and the levels of the customer hierarchy.

The sales dimension could contain the characteristics ‘sales person’, ‘sales group’ and ‘sales office’.                                            

The time dimension could be given using the characteristics ‘day’ (in the form YYYYMMDD), ‘week’ (in the form YYYY.WW), ‘month’ (in the form YYYY.MM), ‘year’ (in the form YYYY) and ‘period’ (in the form YYYY.PPP).

Use

When defining an InfoCube, characteristics for dimensions are grouped together to enable them to be stored in a star schema table (dimension table). The aforementioned business-orientated grouping can be the basis for this. With the aid of a simple foreign key dependency, dimensions are linked to one of the key fields of the fact table.

Also refer to Star Schema.

Structure

From a technical viewpoint several characteristic values are mapped to an abstract dimension key (DIM ID), to which the values in the fact table refer. The characteristics chosen for an InfoCube are divided up among InfoCube-specific dimensions when creating the InfoCube.

Also refer to the following for specific cases arising when defining dimensions:

Line Item and High Cardinality