Observational Health Data Sciences and Informatics

Add records for Ingredients and Drug forms containing standard units for each ingredient.

Define convention for quantity: Either as number of product unites, or as amount of ingredient. See below.

Remove effective_drug_dose.

Introduce verbatim_end_date. drug_exposure_end_date would no longer be nullable, and contain the verbatim, start_date+days_supply or a value that was determined through some ETL heuristic