Modeling Non-Cumulatives with Non-Cumulative Key Figures
A non-cumulative key figure is modeled in BW using the corresponding field for the non-cumulative value change or the corresponding fields for inflows or outflows. You can determine the current non-cumulative or the non-cumulative at a particular point in time. You can do this from the current, end non-cumulative and the non-cumulative changes and/or the inflows and outflows.
The target of the special folder for non-cumulative key figures is to optimize the data transport into the BW system, to retain data, and to access the database when evaluating for reports in the BW system.
Whether the modeling of non-cumulatives with non-cumulative key figures is useful depends on your scenario. It is recommended that you use non-cumulative key figures for areas in which non-cumulatives do not regularly change completely, for example with warehouse stock (retail) or with the number of employees. For more information, see the extensive comparison in Non-Cumulatives.
Model of Non-Cumulative Key Figures
A non-cumulative InfoCube is modeled with at least one non-cumulative key figure. These non-cumulative key figures are mapped using one key figure for non-cumulative changes or two key figures for inflows and outflows. Which option you choose depends on how you want to evaluate the non-cumulative key figure.
The key figures for non-cumulative value change or for inflows and outflows are normal cumulative key figures that have 'summation'both as aggregation and exception aggregation. Non-cumulative key figures always have summation as standard aggregation (aggregational behavior on the database, for example, upon compression or roll-up of aggregates). However, with reference to a time characteristic, they have an exception aggregation (in reporting) that is not equal to summation, as it would not make sense to cumulate non-cumulatives by time.
Non-cumulative key figures such as Number of Employees are cumulated using characteristics such as Cost Center. However, it is not meaningful to total the number of employees using different periods. With periods, for example, you can form an average.
With the cumulative value Sales Revenue, for example, it makes sense to cumulate the individual sales revenues using different periods, and using characteristics such as Products and Customers.
Example of the difference between non-cumulative and cumulative key figures:
Sales volume (cumulative value):
Sales volume 01.20 + sales volume 01.21 + sales volume 01.23 gives the total sales volume for these three days.
Warehouse stock (non-cumulative key figure):
Stock 01.20 + stock 01.21 + stock 01.23 does not give the total stock for these three days.
Technically, non-cumulatives are stored using a marker for the current time (current non-cumulative) and the storage of non-cumulative changes, or inflows and outflows. The current, valid end non-cumulative (to 12.31.9999) is stored in the marker. You can determine the current non-cumulative or the non-cumulative at a particular point in time. You can do this from the current, end non-cumulative and the non-cumulative changes and/or the inflows and outflows.
Queries for the current non-cumulative can be answered very quickly, since the current non-cumulative is created as a directly accessible value. There is only one marker for each combination of characteristic values that is always updated when the non-cumulative InfoCube (InfoCube that includes the non-cumulative key figures) is compressed. So that access to queries is as quick as possible, compress the non-cumulative InfoCubes regularly. (See Compressing InfoCubes) to keep the marker as current as possible.
For example, in month 03 the marker is read with three non-cumulative changes for a query. In month 04, the marker is updated so that the current marker has to be read with only one non-cumulative change for a query in month five. If the marker is not updated, it still has four non-cumulative changes to read
Data Transfer or Storage, and Aggregation for Non-Cumulative Key Figures
To optimize the data transport and data retention for non-cumulative key figures in the BW system, non-cumulative key figures are treated differently from cumulative values in both technical data transfer and storage:
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Non-cumulative key figures are mapped using one key figure for non-cumulative changes or two key figures for inflows and outflows.
See also: Non-Cumulative Key Figures.
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A non-cumulative InfoCube has to contain a time-reference characteristic, that means there must be a time-reference characteristic for exception aggregation of the non-cumulative key figure.
See also: Time Reference Characteristics.
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A non-cumulative key figure always has a time-related exception aggregation.
See also: Aggregational Behavior of Non-Cumulative Key Figures.
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In specific cases it may be necessary to determine the validity of a non-cumulative.
See also: Validity Area.
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Non-cumulatives are transferred in an initialization run and in the change runs that follow (initialization can also be omitted here).
See also: Transferring Non-Cumulative Data into BW.
In query definition and navigation, there is no difference in the way cumulative and non-cumulative key figures are dealt. Cumulative and non-cumulative key figures can be analyzed at the same time in a query.
The special treatment of non-cumulative key figures is only possible in the InfoCube. DataStore objects do not support this.