The provider is not compatible with the version of

Question

I'm trying to use the Oracle ODP.NET 11g (11.1.0.6.20) Instant Client on my ASP.net project as a Data Provider but when I run the aspx page I get a "The provider is not compatible with the version of Oracle client" error message. Any help would be appreciated.

I've referenced the Data Provider in Visual Studio 2005 and the code behind looks like this:

using Oracle.DataAccess.Client;
..

OracleConnection oOracleConn = new OracleConnection();
oOracleConn.ConnectionString =
    "Data Source=MyOracleServerName;" +
    "Integrated Security=SSPI";
oOracleConn.Open();

//Do Something

oOracleConn.Close();

The error for the page looks like this:

Exception Details: Oracle.DataAccess.Client.OracleException: The provider is not compatible with the version of Oracle client

Source Error: 
Line 21: 
Line 22: 
Line 23:             OracleConnection oOracleConn = new OracleConnection();
Line 24:             oOracleConn.ConnectionString =
Line 25:                 "Data Source=MyOracleServerName;" +

[OracleException (0x80004005): The provider is not compatible with the version of Oracle client]
   Oracle.DataAccess.Client.OracleInit.Initialize() +494
   Oracle.DataAccess.Client.OracleConnection..cctor() +483

Stack Trace: 
[TypeInitializationException: The type initializer for 'Oracle.DataAccess.Client.OracleConnection' threw an exception.]
   Oracle.DataAccess.Client.OracleConnection..ctor() +0
   Boeing.IVX.Web.RoyTesting.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\CE218C\Desktop\IVX.Net\Web\IVX\RoyTesting.aspx.cs:23
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

Answer 1

After several hours of troubleshooting, I found this issue to be caused by having Oracle.DataAccess.dll (v4.0) in my projects bin directory, but the runtime also loading Oracle.DataAccess.dll (v2.x) from the GAC. Removing and readding the Oracle.DataAccess entry in the project references solved the problem for me.

The other files mentioned here did not appear to be necessary in my situation.

UPDATE

The root cause of the "The provider is not compatible with the version of Oracle client" error is (generally) that the managed assembly is attempting to load unmanaged libraries which do not match versions. It appears you can force the Oracle driver to use the correct libraries by specifying the library path in the web.config¹

<configuration>
  <oracle.dataaccess.client>
    <settings>
      <add name="DllPath" value="C:\oracle\bin"/>
      <!-- ... -->
    </settings>
  </oracle.dataaccess.client>
</configuration>

Answer 2

Does the IIS/IWAM user have permissions on the Oracle directory? Can you connect to this data source using another app, such as Excel or Access?

Answer 3

Recently I had to work on an older project where the solution and all contained projects were targeted to x32 platform. I kept on trying to copy Oracle.DataAccess.dll and all other suggested Oracle files on all the places, but hit the wall every time. Finally the bulb in the head lit up (after 8 hours :)), and asked to check for the installed ODAC assemblies and their platform. I had all the 64-bit (x64) ODAC clients installed already but not the 32 bit ones (x32). Installed the 32-bit ODAC and the problem disappeared.

How to check the version of installed ODAC: Look in folder C:\Windows\assembly. The "Processor Architecture" property will inform the platform of installed ODAC.

Eight hours is a long time for the bulb to light up. No wonder I always have to slog at work :).

Answer 4

Also look for IIS Application pool Enable 32-bit true or false flag, when you see this message, some oracle forum directed me for this!

Answer 5

I encountered this problem after I installed Oracle Data Tools for Visual Studio 2015, and then fighting with Oracle for a good hour. I decided to try reinstalling Oracle client again instead of this mess with file copying, config changes, etc., and that worked for me.

Answer 6

I had the same issue with Oracle.DataAccess.dll v4.121.2.0. with 2- homes installation (32 and 64 bit versions). 32-bit version workerd, 64-bit version didn't.

In my case (after 2 days of trying) I found that the problem was permissions on the 64-bit-home version. Many Directories in that version had exclusively overridden permissions where "Authenticated Users" role did not have "Read" access, which is set by default on the parent directory. Those sub-directories included "bin", "network/admin", "nls", "oracore", "RDBMS" and possibly others. I found them by filtering out "ACCESS DENIED" result in "Process Monitor" (Procmon.exe) utility from sysinternals. Once the permissions were inherited from the parent directory to those child subdirectories everything started to work.

I didn't what to override the permissions on the whole oracle home so I did them one directory at a time, but I guess if you don't worry about security so much you can reset it on the whole corresponding oracle home directory.