ORA-12514 TNSlistener does not currently know of service requested in conne

Question

When I connect in command prompt using username,password & Host String(tnsNames.ora). Its succeed as seen below.
C:\>sqlplus sonia/mypass@sonia - In this line First sonia is the userName & second Sonia is the host from the tnsnames.ora
SQL*Plus: Release 11.2.0.2.0 Production on Wed Jul 4 13:12:43 2012
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - ProductionBut When I use the sqlPlus screen to connect to Oracle -
UserNAme - sonia
Password - mypass
HostString - sonia
I am getting ERROR - ORA-12514 TNSlistener does not currently know of service requested in connect descriptor.
I am not getting why I am not able to LOGIN FROM SQLPLUS SCREEN.
I searched on the net, But still No LUck.My database is also started which I find using the C:>sc query OracleServiceXE
tnsnames.ora (LOCATION - C:\oracle\product\10.2.0\client_1\network\admin\tnsnames.ora
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\client_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
SONIA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = sonia)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = SONIA)
tnsNAmes.ora -C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN
XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = sonia)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
ORACLR_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    (CONNECT_DATA =
      (SID = CLRExtProc)
      (PRESENTATION = RO)
Listener.ora -C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN
XE =
SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
      (PROGRAM = extproc)
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
      (PROGRAM = extproc)
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = sonia)(PORT = 1521))
DEFAULT_SERVICE_LISTENER = (XE)I am still confused in that I have two tnsNames.ora in different locations.Is that OK?

Answer 1

hello All,
Thanks you all.
I am succeed in login through SQL PLus Screen. I make the two tnsNames.Ora exactly same. & it worked for me.
TnaNames.Ora
XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = sonia)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
ORACLR_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    (CONNECT_DATA =
      (SID = CLRExtProc)
      (PRESENTATION = RO)
  ) Through Command prompt : -
FIRST LOGIN
C:\>sqlplus sonia/mypass@XE
SQL*Plus: Release 11.2.0.2.0 Production on Fri Jul 6 14:04:35 2012
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - Production
SQL>SECOND LOGIN : -
C:\>sqlplus sonia/mypass@sonia
SQL*Plus: Release 11.2.0.2.0 Production on Fri Jul 6 14:03:50 2012
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - Production
SQL>1) I want to ask that, Now in TnsNames.Ora there is no HostString Exist named Sonia, then how in the second method (SEE ABOVE), I am able to login using sonia.
2) Secondly, I want to know how to get TNS_ADMIN value. I have tried but no output for me (SEE BELOW)
C:\>set TNS_ADMIN=%ORACLE_HOME%\network\admin
C:\>echo %ORACLE_SID%
%ORACLE_SID%
C:\>I have read on the net : - If ORACLE_HOME is not set, the output will simply give back %ORACLE_HOME%. It means my TNS_ADMIN is not set.