Observational Health Data Sciences and Informatics

• Requesters: Frank DeFalco, Patrick Ryan

We propose changes to the tables included in the CDM schema in order to clarify their intent. Specifically we propose that the the cohort, cohort_definition, cohort_attribute and attribute_definition tables move from the CDM specification to the results schema specification. The results schema specification will be managed by a database migration package that will be developed in a separate GitHub repository.

Our proposed conventions are that all tables in the CDM schema should contain data that was derived from the original data source (also referred to as “native schema”) All tables in the RESULTS schema should contain data that was derived from the CDM schema. The RESULTS schema table will include tables for achilles results, cohort generation, heracles results, estimation results, etc.

This is a subtle change but one that provides clear conventions for the intent of the different schemas. The development of the database migration package will also provide a new and useful tool for users to be able to create the necessary tables to use OHDSI tools in a more flexible way. This will remove the current limitation whereas the only way to create RESULTS schema tables is by installing and running the WebAPI. The WebAPI will instead leverage this migration package to validate and migrate the tables required for its operation.

• Install / Migrate CDM schema
• Install / Migrate RESULTS schema