Using Multiple Data Sources in Your Model
The advantages of multiple data sources include:
- measure allocation capabilities
Measures that are not normally related to some parts of the dimensional hierarchy can have values allocated to those parts of the dimension.
For example, suppose your sales-tracking system lacks information about staffing levels at each branch. You include a data source that provides this information so that you can derive valuable information, such as the average sales per employee.
- performance improvements
When you split a single, large data source into smaller, denormalized sources, you can shorten the processing time if the columns in all measure-containing sources are associated with unique levels in the model. This is because Cognos Transformer can associate such measures directly, without confirming their context in the level hierarchy.
- integration of data from various sources
Cognos Transformer does not perform database joins between like-named columns. Rather, it associates the data values in each source with the categories that are generated from the columns. To create source data that joins database tables, use IBM® Cognos Impromptu, IBM Cognos, IBM Cognos Data Manager, IBM Cognos Virtual View Manager, or a data access application.