To create the CDB, Oracle Database must know the names and locations of the files for the CDB root and PDB$SEED.

After the CREATE DATABASE statement completes successfully, you can use PDB$SEED and its files to create new PDBs. You cannot modify the PDB seed after it is created.

You must specify the names and locations of the files for PDB$SEED in one of the following ways:

The ENABLE PLUGGABLE DATABASE SEED FILE_NAME_CONVERT clause of CREATE DATABASE

Oracle Managed Files

The PDB_FILE_NAME_CONVERT initialization parameter

位置位置参数：

The SEED FILE_NAME_CONVERT Clause
The SEED FILE_NAME_CONVERT clause of the CREATE DATABASE statement specifies how to generate the names of the PDB$SEED files using the names of the CDB root files.
Oracle Managed Files
When Oracle Managed Files is enabled, it can determine the names and locations of the PDB$SEED files.
The PDB_FILE_NAME_CONVERT Initialization Parameter
The PDB_FILE_NAME_CONVERT initialization parameter can specify the names and locations of the seed's files.

Creating a CDB Without Using Oracle Managed Files

  USER SYS IDENTIFIED BY sys_password
  USER SYSTEM IDENTIFIED BY system_password
  LOGFILE GROUP 1 ('/u01/logs/my/redo01a.log','/u02/logs/my/redo01b.log') 
             SIZE 100M BLOCKSIZE 512,
          GROUP 2 ('/u01/logs/my/redo02a.log','/u02/logs/my/redo02b.log') 
             SIZE 100M BLOCKSIZE 512,
          GROUP 3 ('/u01/logs/my/redo03a.log','/u02/logs/my/redo03b.log') 
             SIZE 100M BLOCKSIZE 512
  MAXLOGHISTORY 1
  MAXLOGFILES 16
  MAXLOGMEMBERS 3
  MAXDATAFILES 1024
  CHARACTER SET AL32UTF8
  NATIONAL CHARACTER SET AL16UTF16
  EXTENT MANAGEMENT LOCAL
  DATAFILE '/u01/app/oracle/oradata/newcdb/system01.dbf'
    SIZE 700M REUSE AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED
  SYSAUX DATAFILE '/u01/app/oracle/oradata/newcdb/sysaux01.dbf'
    SIZE 550M REUSE AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED
  DEFAULT TABLESPACE deftbs
     DATAFILE '/u01/app/oracle/oradata/newcdb/deftbs01.dbf'
     SIZE 500M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED
  DEFAULT TEMPORARY TABLESPACE tempts1
     TEMPFILE '/u01/app/oracle/oradata/newcdb/temp01.dbf'
     SIZE 20M REUSE AUTOEXTEND ON NEXT 640K MAXSIZE UNLIMITED
  UNDO TABLESPACE undotbs1
     DATAFILE '/u01/app/oracle/oradata/newcdb/undotbs01.dbf'
     SIZE 200M REUSE AUTOEXTEND ON NEXT 5120K MAXSIZE UNLIMITED
  ENABLE PLUGGABLE DATABASE
    SEED
    FILE_NAME_CONVERT = ('/u01/app/oracle/oradata/newcdb/', 
                         '/u01/app/oracle/oradata/pdbseed/')
    SYSTEM DATAFILES SIZE 125M AUTOEXTEND ON NEXT 10M MAXSIZE UNLIMITED
    SYSAUX DATAFILES SIZE 100M
  USER_DATA TABLESPACE usertbs
    DATAFILE '/u01/app/oracle/oradata/pdbseed/usertbs01.dbf'
    SIZE 200M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED
  LOCAL UNDO ON;