Posted by: Sahil Malik [MVP], on 08 Jun 2005 | View original | Bookmarked: 0 time(s)

Connecting Oracle 10g to .NET

Below are someone's successful steps -

First of all, I had to install the client part of Oracle 10g, and I installed everything, just to be sure that I didn't miss anything (485
Megabyte, Oracle Enterprise Manager included).

Then... I wrote this code:

OracleConnection myConnection = new OracleConnection("User
Id=ANDREA;Password=ASDASD;Data Source=WIN2003");
myConnection.Open();

Of course the username ANDREA exists in Oracle, the password is the right one and the server name is WIN2003 (if I ping WIN2003 it replies back correctly). Before trying to connect with .NET I verified that the Oracle Enterprise Manager (java version, not the web version) worked fine.

BUT!!!! I get this error...
ORA-12514: the listener doesn't recognize the requested service in the connection descriptor

(Sorry if the message doesn't match, but I am Italian and my message was in Italian, so I had to translate it!)

I didn't have much luck with google. I tried to look for these keywords

OracleConnection 12514 but I got no results. So I found the solution myself. The Oracle's listener seems to identify the .NET connection using the same entry that you can find in the file "tnsnames.ora". This is my file:

# tnsnames.ora Network Configuration File:
C:\Oracle\product\10.1.0\Client_1\NETWORK\ADMIN\tnsnames.ora
# Generated by Oracle configuration tools.

ORCL_WIN2003 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = WIN2003)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SID = ORCL)
      (SERVER = DEDICATED)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

Do you see that ORCL_WIN2003 Well, THAT is Data Source parameter that must be used in the connection string! That ORCL_WIN2003 is the result of the SID and the host name that you enter when you add a new database in the Oracle Enterprise Manager. So, my advice is: try to connect usingn the Oracle Enterprise Manager first, take a look in the "tnsnames.ora" file and then write your code.

The working version of my code is:

OracleConnection myConnection = new OracleConnection("User
Id=ANDREA;Password=ASDASD;Data Source=ORCL_WIN2003");
myConnection.Open();

Hopefully some one will benefit from this one day :-), plus it is a good peice of info to keep on my blog.

Original thread.

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