OracleConnection.Open is throwing ORA-12541 TNS no listener

30,764

Solution 1

Thanks for all your input. I changed my connection string and it worked. Here its what looks like:

 private static string GetConnectionString()
    {
        return "Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=TestHostName.us.local)(PORT=1523) ) )" +
               "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=CCDB)));User id=UserName; Password=Password; enlist=false; pooling=false;";
    }

Solution 2

You can do this a couple of ways: Using your TNSNames file the data source should specify the TNSHosts entry name (the bit before the first "=" from the tnsnames.ora), not the host name:

connection.ConnectionString = "Data Source=TestingConnect;Persist Security Info=True;" + "User ID=tesName;Password=test"; 

Or you can put the entire TNS entry in the connection string like so:

connection.ConnectionString = "Data Source=(DESCRIPTION = " +
    "(ADDRESS = (PROTOCOL = TCP)(HOST = TestHostName.us.local)(PORT = 1523))" +
    "(CONNECT_DATA =" + 
    "(SERVER = DEDICATED)" + 
    "(SERVICE_NAME = TEST))" + 
    ");Persist Security Info=True;User ID=tesName;Password=test"; 
Share:
30,764
RG-3
Author by

RG-3

Updated on July 09, 2022

Comments

  • RG-3
    RG-3 almost 2 years

    So I am connecting to an external server through C#. I just installed Oracle 11g client on my machine from here: http://www.oracle.com/technetwork/database/windows/downloads/index-090165.html (255MB one).

    After reading many blogs/questions I found this article to be useful:

    http://dbaspot.com/oracle-faq/444787-ora-12541-tns-no-listener.html

    So is this correct? I cannot do anything. The DBA has to edit the LISTENER.ORA file?

    My tnsnames.ora looks like this:

      TestingConnect=
      (DESCRIPTION =
        (ADDRESS = (PROTOCOL = TCP)(HOST = TestHostName.us.local)(PORT = 1523))
        (CONNECT_DATA =
          (SERVER = DEDICATED)
          (SERVICE_NAME = TEST)
        )
      )
    

    It is throwing me the err at:

    Oracle.DataAccess.Client.OracleConnection connection = new Oracle.DataAccess.Client.OracleConnection();
    
    connection.ConnectionString = "Data Source=TestHostName.us.local;Persist Security Info=True;" + "User ID=tesName;Password=test";
    
    connection.Open() //Throwing ERR!!!
    

    What should I do? I appreciate any comments. Thanks!