To adopt a non-CDB as a PDB using the DBMS_PDB package:

1. Create the CDB if it does not exist.

2. Ensure that the non-CDB is in a transactionally-consistent state.

3. Place the non-CDB in read-only mode.

4. Connect to the non-CDB, and run the DBMS_PDB.DESCRIBE procedure to construct an XML file that describes the non-CDB.

   The current user must have SYSDBA administrative privilege. The user must exercise the privilege using AS SYSDBA at connect time.

   For example, to generate an XML file named ncdb.xml in the /disk1/oracle directory, run the following procedure:

   BEGIN
     DBMS_PDB.DESCRIBE(
       pdb_descr_file => '/disk1/oracle/ncdb.xml');
   END;
   /
   

   After the procedure completes successfully, you can use the XML file and the non-CDB database files to plug the non-CDB into a CDB.

5. Run the DBMS_PDB.CHECK_PLUG_COMPATIBILITY function to determine whether the non-CDB is compatible with the CDB.

   When you run the function, set the following parameters:

   • pdb_descr_file - Set this parameter to the full path to the XML file.

   • pdb_name - Specify the name of the new PDB. If this parameter is omitted, then the PDB name in the XML file is used.

   For example, to determine whether a non-CDB described by the /disk1/oracle/ncdb.xml file is compatible with the current CDB, run the following PL/SQL block:

   SET SERVEROUTPUT ON
   DECLARE
     compatible CONSTANT VARCHAR2(3) := 
       CASE DBMS_PDB.CHECK_PLUG_COMPATIBILITY(
              pdb_descr_file => '/disk1/oracle/ncdb.xml',
              pdb_name       => 'NCDB')
       WHEN TRUE THEN 'YES'
       ELSE 'NO'
   END;
   BEGIN
     DBMS_OUTPUT.PUT_LINE(compatible);
   END;
   /
   

   If the output is YES, then the non-CDB is compatible, and you can continue with the next step. If the output is NO, then the non-CDB is not compatible, and you can check the PDB_PLUG_IN_VIOLATIONS view to see why it is not compatible. All violations must be corrected before you continue. For example, any version or patch mismatches should be resolved by running an upgrade or the datapatch utility. After correcting the violations, run DBMS_PDB.CHECK_PLUG_COMPATIBILITY again to ensure that the non-CDB is compatible with the CDB.

6. Shut down the non-CDB.

7. Plug in the non-CDB.

   For example, the following SQL statement plugs in a non-CDB, copies its files to a new location, and includes only the tbs3 user tablespace from the non-CDB:

   CREATE PLUGGABLE DATABASE ncdb USING '/disk1/oracle/ncdb.xml'
     COPY
     FILE_NAME_CONVERT = ('/disk1/oracle/dbs/', '/disk2/oracle/ncdb/')
     USER_TABLESPACES=('tbs3');
   

   If there are no violations, then do not open the new PDB. You will open it in the following step.

   The USER_TABLESPACES clause enables you to separate data that was used for multiple tenants in a non-CDB into different PDBs. You can use multiple CREATE PLUGGABLE DATABASE statements with this clause to create other PDBs that include the data from other tablespaces that existed in the non-CDB.

8. Run the ORACLE_HOME/rdbms/admin/noncdb_to_pdb.sql script. This script must be run before the PDB can be opened for the first time.

   If the PDB was not a non-CDB, then running the noncdb_to_pdb.sql script is not required. To run the noncdb_to_pdb.sql script, complete the following steps:

   1. Access the PDB.

      The current user must have SYSDBA administrative privilege, and the privilege must be either commonly granted or locally granted in the PDB. The user must exercise the privilege using AS SYSDBA at connect time.

   2. Run the noncdb_to_pdb.sql script:

      @$ORACLE_HOME/rdbms/admin/noncdb_to_pdb.sql
      

   The script opens the PDB, performs changes, and closes the PDB when the changes are complete.

9. Open the new PDB in read/write mode.

   You must open the new PDB in read/write mode for Oracle Database to complete the integration of the new PDB into the CDB. An error is returned if you attempt to open the PDB in read-only mode. After the PDB is opened in read/write mode, its status is NORMAL.

10. Back up the PDB.

    A PDB cannot be recovered unless it is backed up.