Define A Calculated Column - IBM Cognos User Manual

Procedure
1. In a Cognos Transformer model, right-click the Dimension Map and click
2. Browse to select a dimensional package and click Finish.
3. In the dimension tree for the package, select the dimensions, hierarchies, or

Define a Calculated Column

A calculated column is an expression that uses other columns, functions, and
constants to derive new data for the model.
Use calculated columns in your dimension structure
v to create exception dimensions, or new ways of slicing and dicing your data
v to create customized date values
v to produce new measure values
When you use a calculated column as a measure, the value is derived before any
rollup takes place. A calculated column is similar to a calculated measure with the
following exception: if the Regular timing of your calculated measure is set to
Before Rollup, no consolidation occurs. For optimal cube size and run-time
performance, calculated columns are preferable to before-rollup calculated
measures.
For more information about calculated measures, see "Define a Calculated
Measure" on page 97.
Note: If currency conversion is supported by your OLAP reporting component, the
calculated column is initially calculated using the default (base) currency. After
that, conversion occurs dynamically, followed by rollup.
Procedure
1. In the Data Sources list, click the data source to make it active and then, from
2. In the Column name box, enter a name for the new column.
3. In the Column type box, click Calculated and click Calculation.
Insert Dimension from Package.
levels that you want to add to your model and click OK.
The dimensions that you selected are added to the Dimension Map, and a
package data source is added to the Data Sources list. A single query for each
dimension is added under the package data source.
Where possible, Cognos Transformer includes the relevant label and business
key as the source column for each level in the imported dimension. Because
different OLAP sources behave differently, you may need to change the query
items used in the source or category code columns for the levels to ensure the
dimension is in scope with the measures for the model.
The import may include more metadata than expected. This allows you to
refine the columns that are used within the dimension.
Tip: To ensure conformed dimensions across different packages, the original
OLAP source should use unique business keys. This will help to ensure that
Cognos Transformer generates category codes that are conformed to the OLAP
source from which the dimension was created.
based on a calculation from existing source columns
the Edit menu, click Insert Column.
Chapter 4. Structuring Your Data Into Dimensions
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