Have found an additional information concerning drugs in source data, if they were brought in by patient himself. This sort of information is presented by flag in source records. During the conversion source records will be used to populate the cdm.drug_exposure, but is seems right to keep an additional information about these drugs in cdm.observation. The idea is to build a fact relationship table to keep a distinct connection between cdm.drug_exposure and cdm.observation records.
The problem is what concept can be used as a relationship_concept_id, which is a required field.
Worth mentioning that the reverse concept is also needed.
Maybe someone has already made something like this and can give me some tips.
Any ideas also will be appreciated!
Thanks in advance!