#1 is the ingredient of a drug
#2 The class_id = Branded Drug Box comes from the vocabulary_id = RxNorm Extension. The RxNorm Extension vocabulary is non-US drugs. If you have US data, then you most likely will not use class_id = Branded Drug Box.
But, since you are trying to decipher the the different class_ids, I will give another example:
Example: your source data has Rx CUI = 209459 or the following string term:
Acetaminophen 500 MG Oral Tablet [Tylenol]
If you were to map to class_id = ingredient, you only get the ingredient data which is ‘acetaminophen’
When you map it to the the exact string term or the Rx CUI = CONCEPT.concept_code the class_id will = Branded Drug. This mapping will result in the inclusion of all the source attributes of the drug ingredient = acetaminophen, dose = 500, dose unit = mg, form = oral tablet, and brand name = Tylenol
No, stay as true to the source term as possible. The OHDSI provided hierarchies in the CONCEPT_ANCESTOR table will give you all the the related data if you need it. It’s easy to go from a Branded Drug to an ingredient/s because it is a 1:1 or an appropriate 1:M relationship. You can NOT accurately go from an ingredient to any other class_id.
The ETL team does the mapping, the end users query the data. I highly suggest the end users review the tutorials or attend the tutorials @krfeeney suggested here.