Designing Cognos Reports using Data Module Best Practices


Here are few learning to make  data module work:-

  • It's better to create query subjects in FM with prompts. That way we can create dataset of smaller size for modeling and avoid using bulky packages. This will also enable to reduce
  •  Always create data set names with query subject name so that easy to define data lineage
  • Instead of using package in data module, try to use data set created based on packages.
  • Arrange dataset in folders based on dependencies so that they can be refreshed in order.
  • Handle nulls either FM or Data modules using package ( use clean up) before creating datasets to avoid unexpected data type errors. 
  • It's important to define right data type for data items for specific purpose to avoid incorrect interpretation and aggregation by data module and data sets.
  • You may need to define different layer of data module to rejoin tables so it's best to move aliases and join to FM to keep Data Module levels to 2-3.



Will keep adding tips as time permits or new insight is discovered.

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