Maybe you could have reason but...it's not so now, sorry.
You are not thinking in the automatic script.
I need to staging 138 tables...do you think really the right way is writing 138 load instructions checking for each table what is the field I have to translate and what no?
Well now seriously, the ONLY working way is a preceding load on an extraction from DWH.
I am writing a script with variables for checking from a list the fields I have to translate. So the script check if the field is in the table or not, modifying loading script according to the situation.