Those of you who used exp/imp know that you had to set the NLS_LANG in the session to obtain a correct export, otherwise it would export in default character-set which is US7ASCII. If you’re importing into a different database with a different character-set, you would have to set NLS_LANG again to the new character-set.
Now with Data Pump, setting NLS_LANG prior to exporting/importing is no longer required. Data Pump would do the conversion for you without any settings from your side.
Here is a quick test we ran:
DB1 character-set: AR8ISO8859P6
DB2 character-set: AL32UTF8
Session NLS_LANG: American_America.WE8ISO8859P1
We were able to export/import tables with Arabic data from/to DB1 & DB2 with no issues.
Senior Oracle DBA