Applymap() is a function that recall previously loaded Mapping table. It have three special properties:
- It only have two columns. The first being the lookup value and the second being the mapping value to return.
- It is a temporary table that is automatically dropped from the data model.
- If no lookup value is found you can define the missing value.
Using Resident and Joining it:
- Loads many fields.
- If no match is found you cannot define a default value.
- In case the Resident table have any duplicate values the Fact table will provide misleading results.
