I am a SQL Server user .
I am on a project that is using oracle (which I rarely use) I need to create an ODBC connection so I can access the some data via MS Access I have a application on my machine called oraHome90. It seems to allow a configuration of something called a listener in a “net configuration utility”, I think that a “Local Net Service Name Configuration” needs to also be done. The IT support gave me this information to set up the ODBC connection . I have tried every combination that I can think of. I can get past a test that successfully passes a test to “login“ to the oracle server database. When I try to create the ODBC connection I get the following error: ORA-12154: TNS: Could not resolve service name.
Assuming that I want to start from scratch and the following information is supposed to allow for me to connect to the database….. Any suggestions or comment ? Note: ultimately the project will have a website .ASP page query the data, but I have to first prove that I can see the data using the ODBC connection via MS Access
Service name: SERVICENAME
HOST = HOST.XYZi.com
User Id: MYUSERID
Password: MYPASSWORD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'Oracle Connection
Dim ocst
Dim oconn
ocst = "Provider=OraOLEDB.Oracle;" & _
"Data Source=DATASOURCE;" & _
"User ID=CHIJXL;" & _
"Password=password;"
set oconn = CreateObject("ADODB.Connection")
The answer is
We resolved our issues by re-installing the Oracle Database Client. Somehow the installation wasn't successful on 1 of the workstations (even though there was no logging), however when comparing size/files/folders of the Oracle directory to a working client workstation, there was a significant amount of files that were missing. Once we performed a clean install, everything worked perfectly.
from http://ora-12154.ora-code.com
ORA-12154: TNS:could not resolve the connect identifier specified
Cause: A connection to a database or other service was requested using a connect identifier, and the connect identifier specified could not be resolved into a connect descriptor using one of the naming methods configured. For example, if the type of connect identifier used was a net service name then the net service name could not be found in a naming method repository, or the repository could not be located or reached.
Action:
If you are using local naming (TNSNAMES.ORA file):
Make sure that "TNSNAMES" is listed as one of the values of the NAMES.DIRECTORY_PATH parameter in the Oracle Net profile (SQLNET.ORA)
Verify that a TNSNAMES.ORA file exists and is in the proper directory and is accessible.
Check that the net service name used as the connect identifier exists in the TNSNAMES.ORA file.
Make sure there are no syntax errors anywhere in the TNSNAMES.ORA file. Look for unmatched parentheses or stray characters. Errors in a TNSNAMES.ORA file may make it unusable.
If you are using directory naming:
Verify that "LDAP" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Verify that the LDAP directory server is up and that it is accessible.
Verify that the net service name or database name used as the connect identifier is configured in the directory.
Verify that the default context being used is correct by specifying a fully qualified net service name or a full LDAP DN as the connect identifier
If you are using easy connect naming:
Verify that "EZCONNECT" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Make sure the host, port and service name specified are correct.
Try enclosing the connect identifier in quote marks. See the Oracle Net Services Administrators Guide or the Oracle operating system specific guide for more information on naming.
I just spend an hour on this, I'm new to Oracle so i was thoroughly confused..
the situation:
just installed visual studio 2012 Oracle developer tools. When i did this I lost the items in my drop down which contained my TNS entries in TOAD. I was getting this error from Visual studio AND TOAD!! WTH! so i added the environmental Variable TNS_ADMIN under "ALL USERS" with the path to my .ora file (which i now worked fine because it worked until I broke it). Toad picked up that change. Still Visual Studio wouldn't give me any love... still getting same error. THEN, i added the environmental Variable TO MY USER VARIABLES.. VIOLA!!
ENSURE THE ENVIRONMENTAL VARIABLES ARE SET FOR THE SYSTEM AND THE USER
I have resolved this issue by removing sqlnet.ora from the C:\oracle\ora92\network\ADMIN path
- Make sure TNSNAMES.ORA file exists in the right directory
- Make sure PATH environment variable is having entry for oracle
- Make sure no syntax issues in the TNSNAMES.ORA
- Try removing sqlnet.ora file
We also had the similar issue. What we found out that we had provided multiple aliases for our connection string in tnsnames.ora, something like:
svc01, svc02=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xxxx)(port=50))(CONNECT_DATA=(SERVER=DEDICATED)(service_name=yyyysvc.world)))
so when creating a connection using ODBC, when we selected the value for TNS service name, the auto populate was showing 'svc01,' (please note the extra comma there). As soon as we removed the comma, it started working for us.
I struggled to resolve this problem for hours until I found an Environment variable called TNS_ADMIN set in My Computer => Properties => Advanced => Environment Variables => look in System variables for an entry called TNS_ADMIN. TNS_ADMIN is added to change the default path for Tnsnames.ora entry. This is useful when its used in a network environment where a generic tnsnames.ora entry can be setup for all the network computers. To look at the default path of tnsnames.ora add the default path in TNS_ADMIN.
I experienced this problem too. I discovered the problem is because Oracle DB does not like the space in C:program files (x86)\Toad...... so I created a new directory named C:App\Toad then reinstalled in it to connect Toad to Oracle. It worked.
I had this problem because of a typo in the filename tsnames.ora instead of tnsnames.ora
Hours of problems SOLVED. I had installed the Beta Entity Framework for Oracle and in in visual studio 2010 MVC 3 project I was referencing under the tab .NET the Oracle.DataAccess ... This kept giving me the "Oracle ORA-12154: TNS: Could not..." error. I finally just browsed to the previous Oracle install under c:\Oracle\product.... using the old 10.2.0.100 version of the dll. Finally it works now. Hope it helps someone else.
@Warren and @DCookie have covered the solution, one thing to emphasise is the use of tnsping. You can use this to prove your TNSNames is correct before attempting to connect.
Once you have set up tnsnames correctly you could use ODBC or try TOra which will use your native oracle connection. TOra or something similar (TOAD, SQL*Plus etc) will prove invaluable in debugging and improving your SQL.
Last but not least when you eventually connect with ASP.net remember that you can use the Oracle data connection libraries. See Oracle.com for a host of resources.
Only restart the SID services. For example you SID name = orcl then all the services which related to orcl should be restart then you problem will be solved
Arrhhh!! I RAN INTO THIS AGAIN!!!
Just install ToadForOracle in C:\ or any directory without parenthesis in the path.
In my case its because I was on a x64 PC and still using the old Oracle 9i with the 32bit drivers!
I am using SQL Reporting Services with an Oracle Database. The problem is the brackets in the path to Visual Studio (BIDS). Oracle doesn't like apps that start in a path with brackets:
RDBMS 10g XE problem with parenthesis in path
So I made a BAT file to open Visual Studio with Progra~2 as the short path name for "Program Files (x86)".
Here is the contents of the BAT file:
rem Progra~2 is short path name for "Program Files (x86)" and works around an Oracle client bug that doesn't like the ()'s in the path
start /B "C:\Progra~2\Microsoft Visual Studio 9.0\Common7\IDE" "C:\Progra~2\Microsoft Visual Studio 9.0\Common7\IDE\devenv.exe"
I name this BAT file StartBIDS.BAT and put it in the directory:
"C:\Program Files\Microsoft SQL Server\Start BIDS.bat"
Then I make a short cut to the BAT file on my Desktop and also my Start Menu and change the ShortCuts icon. This allows me to open TOAD, Visual Studio, BIDS and etc apps that I use to work with Oracle.
Update:
Alternatively make a Junction:
mklink /J "C:\Program Files (x86)\" "C:\Program Files x86\"
Then remove the brackets in the shortcut:
Going on the assumption you're using TNSNAMES naming, here's a couple of things to do:
- Create/modify the tnsnames.ora file in the network/admin subdirectory associated with OraHome90 to include an entry for your oracle database:
> SERVICENAME_alias = > (DESCRIPTION = > (ADDRESS = (PROTOCOL = TCP)(HOST = HOST.XYZi.com)(PORT = 1521)) > (CONNECT_DATA = (SERVICE_NAME = SERVICENAME))
This is assuming you're using the standard Oracle port of 1521. Note that servicename_alias can be any name you want to use on the local system. You may also find that you need to specify (SID = SERVICENAME) instead of (SERVICENAME=SERVICENAME).
- Execute tnsping servicename_alias to verify connectivity. Get this working before going any further. This will tell you if you're past the 12154 error.
- Assuming a good connection, create an ODBC DSN using the control panel, specifying the ODBC driver for Oracle of your choice (generally there's a Microsoft ODBC driver at least, and it should work adequately as a proof of concept). I'll assume the name you gave of DATASOURCE. Use the servicename_alias as the Server name in the ODBC configuration.
- At this point you should be able to connect to your database via Access. I am not a VB programmer, but I know you should be able to go to File->Get External Data->Link Tables and connect to your ODBC source. I would assume your code would work as well.
In my case, the error are because I have 2 Oracle clients, It's the solution:
Oracle ORA-12154 error on local IIS, but not with Visual Studio Development Server
I fixed this problem using this steps.
First of all, this error occured , if you didn't install same directory or drive.
But the answer is here.
- Login windows as a Adminstrator.
- Go to Control Panel.
- System Properties and click Enviroment
Find the OS variable and change name as a "TNS_ADMIN"
And change the value as a "tnsnames's directory address"
Restart the system.
- Congrulations.
If there is a space in the beginning of the tns name define in file tnsnames.ora, then some of the the connectors like odbc may give this error. Remove space character in the beginning.
I had a same problem and the same error was showing up. my TNSNAMES:ORA file was also good to go but apparently there was a problem due to firewall blocking the access. SO a good tip would be to make sure that firewall is not blocking the access to the datasource.
It has nothing to do with a space embedded in the folder structure.
I had the same problem. But when I created an environmental variable (defined both at the system- and user-level) called TNS_HOME and made it to point to the folder where TNSNAMES.ORA existed, the problem was resolved. Voila!
venki
I just spend an hour on this, I'm new to Oracle so i was thoroughly confused..
the situation:
just installed visual studio 2012 Oracle developer tools. When i did this I lost the items in my drop down which contained my TNS entries in TOAD. I was getting this error from Visual studio AND TOAD!! WTH! so i added the environmental Variable TNS_ADMIN under "ALL USERS" with the path to my .ora file (which i now worked fine because it worked until I broke it). Toad picked up that change. Still Visual Studio wouldn't give me any love... still getting same error. THEN, i added the environmental Variable TO MY USER VARIABLES.. VIOLA!!
ENSURE THE ENVIRONMENTAL VARIABLES ARE SET FOR THE SYSTEM AND THE USER
Going on the assumption you're using TNSNAMES naming, here's a couple of things to do:
- Create/modify the tnsnames.ora file in the network/admin subdirectory associated with OraHome90 to include an entry for your oracle database:
> SERVICENAME_alias = > (DESCRIPTION = > (ADDRESS = (PROTOCOL = TCP)(HOST = HOST.XYZi.com)(PORT = 1521)) > (CONNECT_DATA = (SERVICE_NAME = SERVICENAME))
This is assuming you're using the standard Oracle port of 1521. Note that servicename_alias can be any name you want to use on the local system. You may also find that you need to specify (SID = SERVICENAME) instead of (SERVICENAME=SERVICENAME).
- Execute tnsping servicename_alias to verify connectivity. Get this working before going any further. This will tell you if you're past the 12154 error.
- Assuming a good connection, create an ODBC DSN using the control panel, specifying the ODBC driver for Oracle of your choice (generally there's a Microsoft ODBC driver at least, and it should work adequately as a proof of concept). I'll assume the name you gave of DATASOURCE. Use the servicename_alias as the Server name in the ODBC configuration.
- At this point you should be able to connect to your database via Access. I am not a VB programmer, but I know you should be able to go to File->Get External Data->Link Tables and connect to your ODBC source. I would assume your code would work as well.
In reference to #7 in this MSDN POST , adding a registry entry worked for me. I had Vs2010, et oracle 11.0 installed.
Check for the registry key “TNS_ADMIN” at HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE. If it exists then make sure it has the right value as “Dir:\app\product\11.1.0\client_1\network\admin”. If you don’t see the key then create the key and set appropriate value as below. Regedit->HKEY_LOCAL_MACHINE->Software->Oracle->RightClick NEW->StringValue and name it TNS_ADMIN and give the value “X:\app\product\11.1.0\client_1\network\admin”
If you have a 32bit DSN and a 64bit DSN with same names, Windows will automatically choose the 64bit one and If your application is 32bit it shows this error. Just watch out for that.
I had this problem because of a typo in the filename tsnames.ora instead of tnsnames.ora
Arrhhh!! I RAN INTO THIS AGAIN!!!
Just install ToadForOracle in C:\ or any directory without parenthesis in the path.
In my case its because I was on a x64 PC and still using the old Oracle 9i with the 32bit drivers!
I am using SQL Reporting Services with an Oracle Database. The problem is the brackets in the path to Visual Studio (BIDS). Oracle doesn't like apps that start in a path with brackets:
RDBMS 10g XE problem with parenthesis in path
So I made a BAT file to open Visual Studio with Progra~2 as the short path name for "Program Files (x86)".
Here is the contents of the BAT file:
rem Progra~2 is short path name for "Program Files (x86)" and works around an Oracle client bug that doesn't like the ()'s in the path
start /B "C:\Progra~2\Microsoft Visual Studio 9.0\Common7\IDE" "C:\Progra~2\Microsoft Visual Studio 9.0\Common7\IDE\devenv.exe"
I name this BAT file StartBIDS.BAT and put it in the directory:
"C:\Program Files\Microsoft SQL Server\Start BIDS.bat"
Then I make a short cut to the BAT file on my Desktop and also my Start Menu and change the ShortCuts icon. This allows me to open TOAD, Visual Studio, BIDS and etc apps that I use to work with Oracle.
Update:
Alternatively make a Junction:
mklink /J "C:\Program Files (x86)\" "C:\Program Files x86\"
Then remove the brackets in the shortcut:
I had a same problem and the same error was showing up. my TNSNAMES:ORA file was also good to go but apparently there was a problem due to firewall blocking the access. SO a good tip would be to make sure that firewall is not blocking the access to the datasource.
@Warren and @DCookie have covered the solution, one thing to emphasise is the use of tnsping. You can use this to prove your TNSNames is correct before attempting to connect.
Once you have set up tnsnames correctly you could use ODBC or try TOra which will use your native oracle connection. TOra or something similar (TOAD, SQL*Plus etc) will prove invaluable in debugging and improving your SQL.
Last but not least when you eventually connect with ASP.net remember that you can use the Oracle data connection libraries. See Oracle.com for a host of resources.
Going on the assumption you're using TNSNAMES naming, here's a couple of things to do:
- Create/modify the tnsnames.ora file in the network/admin subdirectory associated with OraHome90 to include an entry for your oracle database:
> SERVICENAME_alias = > (DESCRIPTION = > (ADDRESS = (PROTOCOL = TCP)(HOST = HOST.XYZi.com)(PORT = 1521)) > (CONNECT_DATA = (SERVICE_NAME = SERVICENAME))
This is assuming you're using the standard Oracle port of 1521. Note that servicename_alias can be any name you want to use on the local system. You may also find that you need to specify (SID = SERVICENAME) instead of (SERVICENAME=SERVICENAME).
- Execute tnsping servicename_alias to verify connectivity. Get this working before going any further. This will tell you if you're past the 12154 error.
- Assuming a good connection, create an ODBC DSN using the control panel, specifying the ODBC driver for Oracle of your choice (generally there's a Microsoft ODBC driver at least, and it should work adequately as a proof of concept). I'll assume the name you gave of DATASOURCE. Use the servicename_alias as the Server name in the ODBC configuration.
- At this point you should be able to connect to your database via Access. I am not a VB programmer, but I know you should be able to go to File->Get External Data->Link Tables and connect to your ODBC source. I would assume your code would work as well.
This error message can be very confusing and the solution can be surprisingly primitive.
In my case: Oracle stored procedure sends recordset to MS Excel via "Provider=OraOLEDB.Oracle;Data Source= ...etc" .
The problem was a number of decimal numbers in the Oracle data column sent to Excel 2010. When I used Oracle SQL query ROUND(grosssales_eur,2) AS grosssales_eur, it worked fine.
I fixed this problem using this steps.
First of all, this error occured , if you didn't install same directory or drive.
But the answer is here.
- Login windows as a Adminstrator.
- Go to Control Panel.
- System Properties and click Enviroment
Find the OS variable and change name as a "TNS_ADMIN"
And change the value as a "tnsnames's directory address"
Restart the system.
- Congrulations.
We resolved our issues by re-installing the Oracle Database Client. Somehow the installation wasn't successful on 1 of the workstations (even though there was no logging), however when comparing size/files/folders of the Oracle directory to a working client workstation, there was a significant amount of files that were missing. Once we performed a clean install, everything worked perfectly.
Only restart the SID services. For example you SID name = orcl then all the services which related to orcl should be restart then you problem will be solved
If you have a 32bit DSN and a 64bit DSN with same names, Windows will automatically choose the 64bit one and If your application is 32bit it shows this error. Just watch out for that.
This error message can be very confusing and the solution can be surprisingly primitive.
In my case: Oracle stored procedure sends recordset to MS Excel via "Provider=OraOLEDB.Oracle;Data Source= ...etc" .
The problem was a number of decimal numbers in the Oracle data column sent to Excel 2010. When I used Oracle SQL query ROUND(grosssales_eur,2) AS grosssales_eur, it worked fine.
@Warren and @DCookie have covered the solution, one thing to emphasise is the use of tnsping. You can use this to prove your TNSNames is correct before attempting to connect.
Once you have set up tnsnames correctly you could use ODBC or try TOra which will use your native oracle connection. TOra or something similar (TOAD, SQL*Plus etc) will prove invaluable in debugging and improving your SQL.
Last but not least when you eventually connect with ASP.net remember that you can use the Oracle data connection libraries. See Oracle.com for a host of resources.
from http://ora-12154.ora-code.com
ORA-12154: TNS:could not resolve the connect identifier specified
Cause: A connection to a database or other service was requested using a connect identifier, and the connect identifier specified could not be resolved into a connect descriptor using one of the naming methods configured. For example, if the type of connect identifier used was a net service name then the net service name could not be found in a naming method repository, or the repository could not be located or reached.
Action:
If you are using local naming (TNSNAMES.ORA file):
Make sure that "TNSNAMES" is listed as one of the values of the NAMES.DIRECTORY_PATH parameter in the Oracle Net profile (SQLNET.ORA)
Verify that a TNSNAMES.ORA file exists and is in the proper directory and is accessible.
Check that the net service name used as the connect identifier exists in the TNSNAMES.ORA file.
Make sure there are no syntax errors anywhere in the TNSNAMES.ORA file. Look for unmatched parentheses or stray characters. Errors in a TNSNAMES.ORA file may make it unusable.
If you are using directory naming:
Verify that "LDAP" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Verify that the LDAP directory server is up and that it is accessible.
Verify that the net service name or database name used as the connect identifier is configured in the directory.
Verify that the default context being used is correct by specifying a fully qualified net service name or a full LDAP DN as the connect identifier
If you are using easy connect naming:
Verify that "EZCONNECT" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Make sure the host, port and service name specified are correct.
Try enclosing the connect identifier in quote marks. See the Oracle Net Services Administrators Guide or the Oracle operating system specific guide for more information on naming.
I have resolved this issue by removing sqlnet.ora from the C:\oracle\ora92\network\ADMIN path
- Make sure TNSNAMES.ORA file exists in the right directory
- Make sure PATH environment variable is having entry for oracle
- Make sure no syntax issues in the TNSNAMES.ORA
- Try removing sqlnet.ora file
It has nothing to do with a space embedded in the folder structure.
I had the same problem. But when I created an environmental variable (defined both at the system- and user-level) called TNS_HOME and made it to point to the folder where TNSNAMES.ORA existed, the problem was resolved. Voila!
venki
@Warren and @DCookie have covered the solution, one thing to emphasise is the use of tnsping. You can use this to prove your TNSNames is correct before attempting to connect.
Once you have set up tnsnames correctly you could use ODBC or try TOra which will use your native oracle connection. TOra or something similar (TOAD, SQL*Plus etc) will prove invaluable in debugging and improving your SQL.
Last but not least when you eventually connect with ASP.net remember that you can use the Oracle data connection libraries. See Oracle.com for a host of resources.
I struggled to resolve this problem for hours until I found an Environment variable called TNS_ADMIN set in My Computer => Properties => Advanced => Environment Variables => look in System variables for an entry called TNS_ADMIN. TNS_ADMIN is added to change the default path for Tnsnames.ora entry. This is useful when its used in a network environment where a generic tnsnames.ora entry can be setup for all the network computers. To look at the default path of tnsnames.ora add the default path in TNS_ADMIN.
This was mentioned in a comment to another answer, but I wanted to move it to an actual answer since this was also the problem in my case and I would have upvoted it if it had been an answer.
I'm on Linux and the tnsnames.ora file was not set to readable by everyone. After making it readable connecting via tns locally worked.
$ chmod +r tnsnames.ora
Going on the assumption you're using TNSNAMES naming, here's a couple of things to do:
- Create/modify the tnsnames.ora file in the network/admin subdirectory associated with OraHome90 to include an entry for your oracle database:
> SERVICENAME_alias = > (DESCRIPTION = > (ADDRESS = (PROTOCOL = TCP)(HOST = HOST.XYZi.com)(PORT = 1521)) > (CONNECT_DATA = (SERVICE_NAME = SERVICENAME))
This is assuming you're using the standard Oracle port of 1521. Note that servicename_alias can be any name you want to use on the local system. You may also find that you need to specify (SID = SERVICENAME) instead of (SERVICENAME=SERVICENAME).
- Execute tnsping servicename_alias to verify connectivity. Get this working before going any further. This will tell you if you're past the 12154 error.
- Assuming a good connection, create an ODBC DSN using the control panel, specifying the ODBC driver for Oracle of your choice (generally there's a Microsoft ODBC driver at least, and it should work adequately as a proof of concept). I'll assume the name you gave of DATASOURCE. Use the servicename_alias as the Server name in the ODBC configuration.
- At this point you should be able to connect to your database via Access. I am not a VB programmer, but I know you should be able to go to File->Get External Data->Link Tables and connect to your ODBC source. I would assume your code would work as well.
If there is a space in the beginning of the tns name define in file tnsnames.ora, then some of the the connectors like odbc may give this error. Remove space character in the beginning.
This was mentioned in a comment to another answer, but I wanted to move it to an actual answer since this was also the problem in my case and I would have upvoted it if it had been an answer.
I'm on Linux and the tnsnames.ora file was not set to readable by everyone. After making it readable connecting via tns locally worked.
$ chmod +r tnsnames.ora
In my case, the error are because I have 2 Oracle clients, It's the solution:
Oracle ORA-12154 error on local IIS, but not with Visual Studio Development Server
from http://ora-12154.ora-code.com
ORA-12154: TNS:could not resolve the connect identifier specified
Cause: A connection to a database or other service was requested using a connect identifier, and the connect identifier specified could not be resolved into a connect descriptor using one of the naming methods configured. For example, if the type of connect identifier used was a net service name then the net service name could not be found in a naming method repository, or the repository could not be located or reached.
Action:
If you are using local naming (TNSNAMES.ORA file):
Make sure that "TNSNAMES" is listed as one of the values of the NAMES.DIRECTORY_PATH parameter in the Oracle Net profile (SQLNET.ORA)
Verify that a TNSNAMES.ORA file exists and is in the proper directory and is accessible.
Check that the net service name used as the connect identifier exists in the TNSNAMES.ORA file.
Make sure there are no syntax errors anywhere in the TNSNAMES.ORA file. Look for unmatched parentheses or stray characters. Errors in a TNSNAMES.ORA file may make it unusable.
If you are using directory naming:
Verify that "LDAP" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Verify that the LDAP directory server is up and that it is accessible.
Verify that the net service name or database name used as the connect identifier is configured in the directory.
Verify that the default context being used is correct by specifying a fully qualified net service name or a full LDAP DN as the connect identifier
If you are using easy connect naming:
Verify that "EZCONNECT" is listed as one of the values of the NAMES.DIRETORY_PATH parameter in the Oracle Net profile (SQLNET.ORA).
Make sure the host, port and service name specified are correct.
Try enclosing the connect identifier in quote marks. See the Oracle Net Services Administrators Guide or the Oracle operating system specific guide for more information on naming.
In reference to #7 in this MSDN POST , adding a registry entry worked for me. I had Vs2010, et oracle 11.0 installed.
Check for the registry key “TNS_ADMIN” at HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE. If it exists then make sure it has the right value as “Dir:\app\product\11.1.0\client_1\network\admin”. If you don’t see the key then create the key and set appropriate value as below. Regedit->HKEY_LOCAL_MACHINE->Software->Oracle->RightClick NEW->StringValue and name it TNS_ADMIN and give the value “X:\app\product\11.1.0\client_1\network\admin”
We also had the similar issue. What we found out that we had provided multiple aliases for our connection string in tnsnames.ora, something like:
svc01, svc02=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xxxx)(port=50))(CONNECT_DATA=(SERVER=DEDICATED)(service_name=yyyysvc.world)))
so when creating a connection using ODBC, when we selected the value for TNS service name, the auto populate was showing 'svc01,' (please note the extra comma there). As soon as we removed the comma, it started working for us.
Hours of problems SOLVED. I had installed the Beta Entity Framework for Oracle and in in visual studio 2010 MVC 3 project I was referencing under the tab .NET the Oracle.DataAccess ... This kept giving me the "Oracle ORA-12154: TNS: Could not..." error. I finally just browsed to the previous Oracle install under c:\Oracle\product.... using the old 10.2.0.100 version of the dll. Finally it works now. Hope it helps someone else.
Source: Stackoverflow.com