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Saturday, June 30, 2018

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


ORA-12154 occurs when the transparent network substrate (TNS) cannot resolve the service name. The service name is specified in the TNSNames.ora file, which is located in your %ORACLE_HOME%\network\admin\ folder. Most often, this error occurs when information in the TNSNames.ora file is incorrect. For example:
  • The .world extension is not included on the database name.
  • The SERVICE_NAME or HOST variable is incorrect.
To resolve this issue, try one of the three following troubleshooting options, in the order listed below.
Option 1: Edit TNSNames.ora
 Provide the full database name, including the .world extension in both of the following locations:
  • The TNSNames.ora file.
And
  • The Server text box of the Connect page.
Option 2: Ensure that Tableau Server Run As User account has permissions to TNSNames.ora (Tableau Server only)
If you have Tableau Server installed, complete the procedure below to ensure that the Tableau Server Run As user account has permissions to the location of the TNSNames.ora file. If the Run As user account does not have permissions, Tableau Server is unable to access the Oracle Data source details.
Step 1 
Verify the location of the TNSNames.ora file, or the equivalent SQLNET.ora and LDAP.ora files on the machine.
Note: By default, the TNSNames.ora file is located in <oracle-directory>\network\admin directory. For example, C:\Oracle_Client\network\admin.
Step 2 
Confirm that the TNS_ADMIN variable points to the location of the file or files described in step 1.
Note: To check the TNS_ADMIN variable, click the Start button, and select Control Panel > System. Click Advanced system settings, click the Advanced tab, and click Environmental Variables button.
Step 3 
On the Windows Start button, select Tableau Server <version> > Configure Tableau Server.
Step 4 
Under Server Run As User, copy the information in the User text box.
Step 5 
Go to the folder where the TNSNames.ora file is located.
Step 6 
Right-click the folder and select Properties. Click the Security tab and click the Edit button.
Step 7 
Under Group or user names, click the Add button.
Step 8 
In the Enter the object names to select text box, paste the details of the Run As User account you copied in step 6.
Step 9 
When finished, click OK.
Step 10 
In the Permissions area,ensure that the Full control and Modify check boxes are selected.
Step 11 
Click OK to close the dialog boxes.

Option 3: Verify that all information in TNSNames.ora is correct
 If the above troubleshooting steps do not resolve the issue, continue reading and complete the procedure to verify the other information in the TNSNames.ora file is provided correctly.
An example of a TNSNames.ora file is shown here:
QAORCL10.world =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = MY_HOST_NAME)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = MY_SERVICE_NAME)
)
)
The three variables of interest in the file are HOST, PORT, and SERVICE_NAME. Copy these variables from the TNSNames.ora file and keep them available. These variables are case sensitive.The following steps describe how to provide these variables for your connection.
Step 1 
From the Tableau Desktop start page, select Connect to Data.
Step 2 
On the Connect page, click Oracle.
Step 3 
Provide the following information from the TNSNames.ora file:
  • In the Server name text box, type the HOST name.
  • In the Service text box, type the SERVICE_NAME.
  • In the Port text box, type the PORT number.
  • Specify whether to use Windows Authentication or a specific user name and password, and then click Connect.
Note: Variables are case sensitive.
Step 4 
Select a schema from the Schema drop-down list, drag a table to the join area, and then click Go to Worksheet.
Step 5 
Important: 
  • Make sure that you save the TNSNames.ora file you use in ASCII encoding. Any other encoding besides ASCII, for example UTF-8 or Unicode, causes the ORA-12154 error message.
  • These steps are usually required even if the Oracle software is already installed on the machine.
Step 6
Download and install the appropriate Oracle drivers from the Tableau Drivers page. Even if an Oracle driver is installed on your computer, it could be incompatible with Tableau and will require the version specified on the Drivers page.

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