A multitenant container database (CDB) is an Oracle database that includes zero, one, or many user-created pluggable databases (PDBs). A PDB is a portable set of schemas, schema objects, and nonschema objects that appear to an Oracle Net client as a non-CDB. A non-CDB is an Oracle database that is not a CDB.
You can use Data Pump to migrate all, or portions of, a database from a non-CDB into a PDB, between PDBs within the same or different CDBs, and from a PDB into a non-CDB. In general, using Data Pump with PDBs is identical to using Data Pump with a non-CDB.
In Oracle Database 12c Release 1 (12.1), Data Pump does not support any CDB-wide operations. Data Pump issues the following warning if you are connected to the root or seed database of a CDB:
ORA-39357: WARNING: Oracle Data Pump operations are not typically needed when connected to the root or seed of a container database.