In Oracle 12c multitenant databases CDB and PDBs use initialization parameters to control their behavior.   Initialization Parameters for CDB and PDB have the following characteristics:

1. CDB will have one SPFILE.
2. PDB does not have an SPFILE.
3. PDB inherit initialization parameters from their CDB.
4. Most initialization parameters can be changed at the PDB level, these parameters that can have a value of TRUE in the column ISPDB_MODIFIABLE column of V$SYSTEM_PARAMETER view.
5. Changing initialization parameters use the ALTER SYSTEM command with scope of SPFILE or BOTH and they survive system reboot.

Larry Catt

OCP