When selecting the database character set for the CDB, you must consider the current character sets of the databases that you want to consolidate (plug) into this CDB. Oracle recommends AL32UTF8 for the CDB database character set and AL16UTF6 for the CDB national character set because they provide the most flexibility.
When the character set of the CDB root is AL32UTF8, PDBs that are plugged into the CDB can have a different character set from the CDB root. PDBs that are created from PDB$SEED inherit the AL32UTF8 character set from it, but you can migrate the PDB to a different character set. When the character set of the root is not AL32UTF8, all PDBs in the CDB use the character set of the CDB roo
When moving a non-CDB to a CDB, it is best to migrate the non-CDB to AL32UTF8 first. You can use Oracle Database Migration Assistant for Unicode (DMU) to migrate a non-CDB to AL32UTF8. After a CDB is created, you cannot migrate the character set of the CDB using DMU.
