I am using Toad to connect my database and its working fine for me . But when i try to connect with the same credential , i am getting the error message as shown below:

ORA-12154 TNS: could not resolve the connect identifier specified  


  1. Opened command promt
  2. Reach to the path of SQLPLUS (C:\programs\Oracle\Ora11g\BIN)
  3. C:\programs\Oracle\Ora11g\BIN\sqlplus username@schema_name
  4. Enter Password :

    ERROR: ORA-12154 TNS: could not resolve the connect identifier specified

  5. But when i open this with the owner of the schema ,it works for me

  6. C:\programs\Oracle\Ora11g\BIN\sqlplus schema_name@schema_name

  7. Enter Password:

  8. Connected to :......................

So,my question is why my username is not able to connect that particular schema ,while the owner of that schema can connect . Note:I can connect to that schema with my username with Toad ,but not with sqlplus

My TNSNAME.ORA is under TNS_ADMIN folder

Please help me out of this .

2 Answers 2


Actually through toad you are able to login because ORACLE_HOME was set there. but once you're trying to use $ORACLE_HOME/bin, your home is not set properly.

To resolve this, first export $ORACLE_HOME and $ORACLE_SID then try, it should be fine.


So you don't need to specify the full path when you run sqlplus.exe:

Set your %TNS_ADMIN% variable to the full path of the relevant folder (C:\programs\Oracle\Ora11g\TNS_ADMIN ?). Instructions for doing so are a google away. At the same time, make sure %ORACLE_HOME% is set to C:\programs\Oracle\Ora11g and that your %PATH% has C:\programs\Oracle\Ora11g\bin added to it.

The problem you're actually having is because of the parameters you're passing to sqlplus.

You've been doing:

C:\programs\Oracle\Ora11g\BIN\sqlplus username@schema_name

Which is wrong & interpreted by sqlplus as:

C:\programs\Oracle\Ora11g\BIN\sqlplus username@database_name

Also, in Oracle, the owner of a schema (hence the schema name) is the user name. Obviously, grants can be given to other users to perform DML/DDL on other schemas, but you still have to login with a user with sufficient rights. (Proxy logins exist, as does alter session set current_schema=blah, but both are beyond the scope of this answer).

  • 3
    :Sorry for your time,but my problem is with my password ,that contain @ and thats why its giving me this error .@ is read as special character in sqlplus,it try to open something .. Feb 18, 2013 at 16:50
  • Like Gaurav Soni, I've also seen this issue caused by a password containing an '@'. Either: 1. Change the password or 2. When you enter it interactively in sqlplus, add a double-quote to the beginning and end of the password.
    – John King
    Oct 19, 2015 at 16:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.