DataViz Migration - migrating from Cognos to Power BI
IBM Cognos Analytics platforms typically hold several years’ worth of business modeling: Frameworks, hierarchies, calculations, dimensions, measures, variables, and reports.
{openAudit} analyzes Cognos Frameworks, reports, and usage logs to reconstruct the dependencies between data sources, business objects, and reporting outputs.
Key point: in most Cognos estates, the value lies more in the Frameworks and business rules than in the reports themselves.
Analysis of the Cognos estate
The analysis covers Framework Manager, reports, queries, dimensions, hierarchies, calculations, filters, and variables.
The collected metadata makes it possible to reconstruct:
- dependencies between objects;
- relationships with data sources;
- business objects and indicators exposed in reports.
Scope rationalization
Usage logs are cross-referenced with the platform’s metadata.
This phase identifies unused reports, duplicates, and obsolete Frameworks.
Result: the scope that’s actually used is isolated before migration.
Conversion to Power BI
Cognos Frameworks are analyzed and then converted to the target Power BI model.
Dimensions, hierarchies, measures, calculations, variables, and relationships between objects are reconstructed in the target semantic model.
Cognos expressions are converted to SQL or DAX depending on their nature.
Dependencies between Frameworks, reports, and data sources are preserved in the generated model.
Key point: business objects and calculation rules are reconstructed directly from the Cognos Frameworks.
Validation
Migrations can be carried out with dual Cognos / Power BI execution.
The indicators produced by both platforms are compared during acceptance testing phases.
Typical use case: progressive validation of reports before cutover.
Usage-driven migration
Reports can be migrated in batches based on how often they’re used and their business criticality.
Observed usage forms the basis for project planning and development prioritization.
Result: a reduced volume to migrate, with effort focused on active usage.
