Database Software

Okay, I initially had other problem which eventually lead me to this. You can get the overview of it here:

Now, I have another problem, how can I now connect to the PDB database named PDBORCL as mentioned in the guide: https://oracle-base.com/articles/12c/multitenant-connecting-to-cdb-and-pdb-12cr1

I have already changed the content of my tnsnames.ora to

# tnsnames.ora Network Configuration File: /bkofa/oracle/app/oracle/product/12.1.0/dbhome_1/network/admin/tnsnames.ora  
# Generated by Oracle configuration tools.  

ORCL12 =  
  (DESCRIPTION =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = afxortsts)(PORT = 1523))  
    (CONNECT_DATA =  
      (SERVER = DEDICATED)  
      (SERVICE_NAME = orcl12)  
    )  
  )  

PBDORCL =  
  (DESCRIPTION =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = afxortsts)(PORT = 1523))  
    (CONNECT_DATA =  
      (SERVER = DEDICATED)  
      (SERVICE_NAME = pdborcl)  
    )  
  )  

but that didn't work. I also tried to change the listener.ora file as:

# listener.ora Network Configuration File: /bkofa/oracle/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora  
# Generated by Oracle configuration tools.  

LISTENER =  
  (DESCRIPTION_LIST =  
    (DESCRIPTION =  
      (ADDRESS = (PROTOCOL = TCP)(HOST = afxortsts)(PORT = 1523))  
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))  
    )  
  )  

SID_LIST_LISTENER =  

  (SID_LIST =  

    (SID_DESC =  

      (GLOBAL_DBNAME = pdborcl)  

      (SID_NAME = pdborcl)  

    )  

  )  

But then I encounter:

ORA-01034: ORACLE not available  
ORA-27101: Shared memory realm does not exist  
SVR4 Error: no such file or directory  
Additional information: 2581  

By the way, this is is number of containers on my DB so far:

SELECT name, pdb  
FROM   v$services  
ORDER BY name;  

NAME              PDB  

SYS$BACKGROUND    CDB$ROOT  
SYS$USERS         CDB$ROOT  
orcl12            CDB$ROOT  
orcl12XDB         CDB$ROOT  
pdborcl           PDBORCL