Frequently Asked Questions

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  • I am familiar with SQL Server's .NET data provider, but am new to Oracle. Is it easy to learn to use ODP.NET?

    Yes. ODP.NET inherits from all the ADO.NET base classes, which is what SQL Server's .NET data provider, SqlClient, is based upon. The ADO.NET constructors, methods, and properties that you use with SQL Server will be the same with Oracle. For many applications, the only notable differences will be having all objects that were preceded with "Sql", such as SqlConnection, be preceded by "Oracle", such as OracleConnection, and accounting for differences between Oracle and SQL Server database data types, SQL, and stored procedure calls. With ADO.NET 2.0 factory classes, many of these differences go away and make it even easier to use ODP.NET.

  • What are the different ways Oracle integrates with Microsoft .NET?

    Oracle integrates with .NET in a number of ways. For optimized .NET data access, ODP.NET enables access to all of the Oracle database's advanced features, such as RAC and XML DB, while ensuring the fastest performance from the .NET Framework.

    For .NET development tools that make Oracle easier to use, the Oracle Developer Tools for Visual Studio .NET provide wizards and designers that auto-generate ODP.NET code and can browse and edit schemas and stored procedures. Additionally, it includes a Data Window to modify and view data and context-sensitive help.

    Beginning with Oracle Database 10g Release 2, developers can build and deploy .NET stored procedures for their Oracle database.

    For application integration, web services can facilitate integration between your existing Oracle and .NET applications.

  • Are all these Oracle on .NET features part of Oracle Database Express Edition (XE)?

    ODP.NET, Oracle Developer Tools for Visual Studio .NET, and .NET stored procedures are all included as part of Oracle Database XE.

  • Where can I find ODP.NET help and sample code?

    ODP.NET documentation is available from within Visual Studio .NET using Dynamic Help. Just hit the F1 key when your cursor is on an ODP.NET API and a help page for that API will appear right within Visual Studio .NET.

    Additional ODP.NET documentation is available both locally installed and from the ODP.NET documentation page.

    Sample code can be found both locally as part of the ODP.NET installation (e.g. <Oracle Home>\ODACsamples\\ or <Oracle Home>\ODACsamples\\samples\).

    ODP.NET users can ask questions on the ODP.NET discussion forum.

  • I have ODP.NET installed, but I can't find the ODP.NET Dynamic Help. Where is it?

    This behavior sometimes occurs when installing new Visual Studio .NET versions over an ODP.NET installation. To enable ODP.NET Dynamic Help, go to Visual Studio .NET Combined Help Collection Manager located in Visual Studio .NET 2002, Visual Studio .NET 2003, or Visual Studio 2005. Make sure the box next to the Oracle Data Provider for .NET Help is checked and click on the Update VSCC button. Close Visual Studio .NET and re-open it to enable ODP.NET Dynamic Help.

    Note: Because of security restrictions, you may need to copy and paste the links above to a browser, rather than clicking on them. Once copied to a local browser, if you have a Windows service pack that prevents active content (e.g. Windows XP service pack 2), you will need to allow active content to view the complete page. To do this, click on the yellow bar at the top of the Visual Studio .NET Combined Help Collection Manager page, which indicates active content has been blocked. Select "Allow Blocked Content". A security warning will show up. Click "Yes" and you will be able to view the page in its entirety, including having the option to incorporate the Oracle Data Provider for .NET Help into Visual Studio .NET.

  • What are the new features in this version of ODP.NET?

    New ODP.NET features organized by release can be found here.

  • How do I make a feature enhancement request for ODP.NET?

    You can email the ODP.NET product manager, alex.keh [at], with any ODP.NET feature requests you have.

  • What features will ODP.NET support in future releases?

    In general, Oracle does not discuss features in future product releases until the release date nears. We are well aware of enhancement requests made through the ODP.NET discussion forum and Oracle support. We encourage Oracle users to continue to make their requests known. Oracle will do its best to fulfill these requests in future releases.

Configuration and Certification

  • What versions of ODP.NET support ADO.NET 2.0 and 3.0?

    Beginning with ODP.NET, ADO.NET 2.0 and 1.x are supported, each with its own set of ODP.NET binaries. For example, in ODP.NET, Oracle.DataAcess.dll 1.102.2.x supports the .NET Framework 1.x and Oracle.DataAcess.dll 2.102.2.x supports the .NET Framework 2.0. Oracle will continue releasing new providers for ADO.NET 1.x in future releases.

    With the introduction of .NET 3.0, Oracle has certified ODP.NET for .NET 3.0. No Oracle code or configuration changes are required if your application already works with .NET 2.0.

  • Does ODP.NET support Windows Vista? If so, what versions of ODP.NET?

    For ADO.NET 1.x, ODP.NET for Windows Vista is included as part of Oracle Database 10g Release 2 (, which can be downloaded from OTN.

    For 32-bit ADO.NET 2.0 and higher, Oracle Data Access Components (ODAC) and Oracle Database 11g support Windows Vista. ODAC or higher can be downloaded from the ODAC download page.

  • In ODP.NET and higher, why does the same ODP.NET provider have two different version numbers?

    For ODP.NET and higher, the same ODP.NET binaries have two different version numbers when viewed from either .NET products (e.g. Visual Studio 2005 would see version or when viewed from Oracle products (e.g. Oracle Universall Installer would see version Prior to ODP.NET, the latter versioning was employed exclusively. The use the second versioning method was necessary to properly support .NET policy files for .NET Framework 1.x and 2.0.

    For further details, read the versioning scheme section of Chapter 2 of the Oracle Data Provider for .NET ( or higher) Developer's Guide .

  • Do I need to install ODP.NET on my Oracle database server?

    No. You only need to install ODP.NET for running client or middle-tier .NET applications. The exception is if you are using .NET stored procedures in the database server. The server-side ODP.NET provider will automatically be installed with the Oracle Database Extensions for .NET.

  • Can ODP.NET work with Oracle8, Oracle8 i, Oracle9 i, and Oracle10 g database (DB) servers? Can these DB servers be on Linux or Unix?

    Yes and yes. Oracle clients can support older and newer versions of the Oracle database. Consult the Oracle on Windows FAQ for more information.

    Oracle clients on Windows can work with Oracle database servers on any platform.

  • Can ODP.NET be used with an Oracle8, Oracle8 i, or Oracle9 i Release 1 client?

    No. You need to use the Oracle9 i Release 2 or higher client.

  • What do I need to have installed on my client machine to have ODP.NET work?

    You will require the following:

    • Windows Operating Sytem
    • 32-bit: Windows Vista (Business, Enterprise, and Ultimate Editions), Windows Server 2003, Windows Server 2003 R2, Windows XP Professional, or Windows 2000
    • 64-bit AMD64/EM64T: Windows Server 2003 x64, Windows Server 2003 R2 x64, or Windows XP x64
    • 64-bit Itanium: Windows Server 2003
    • Microsoft .NET Framework 1.0 or higher
    • Oracle9 i Client Release 2 (9.2) or higher (included with ODP.NET installation)
    • Oracle Net Services (included with ODP.NET installation)
    • Oracle Services for Microsoft Transaction Server, Release 2 (9.2) or higher. This is required for applications using distributed transacations.
  • Is 64-bit ODP.NET supported?

    64-bit ODP.NET for 64-bit Windows x64 (AMD64 and EM64T) and for 64-bit Windows Itanium can be downloaded here.

Common Runtime Issues

  • How do I use distributed transactions with ODP.NET?

    The Oracle Services for MTS (OraMTS) is required for distributed transaction support with COM+/Enterprise Services/Microsoft Transaction Server. OraMTS is available to download for free on OTN.

  • I have two .NET applications on the same machine running two different versions of ODP.NET. How do I ensure both these applications use the correct ODP.NET version?

    Beginning with ODP.NET, the Oracle installer will register the following publisher policy DLLs in the Global Assembly Cache (GAC) that redirect 9.2, 10.1 and 10.2 ODP.NET applications to use the last installed version of ODP.NET: Policy.9.2.Oracle.DataAccess.dll and Policy.10.1.Oracle.DataAccess.dll.

    ODP.NET 9.2 includes just the first policy DLL above. These policy files ensure that all your ODP.NET applications use the most recently installed version of ODP.NET.

    You may undo the redirection manually. Policy DLLs can be de-installed through gacutil.exe using the /u option. Another approach is to navigate to the GAC directory (i.e. C:\WINNT\assembly) through the Windows Explorer and delete the policy folders. That will eliminate any policy enforcement for all your ODP.NET applications.

    If you have applications on the same machine using different ODP.NET versions, you should create an application-specific policy file.

  • How can I run two applications concurrently when each one uses different unmanaged Oracle clients installed side by side?

    ODP.NET consists of both managed (Oracle.DataAccess.dll) and unmanaged .NET files. Follow these steps to be able to run multiple applications concurrently with different Oracle client versions. These instructions apply when using two or more versions of Oracle Client on the same machine.

    Note: Make sure your .NET policy files refer to the ODP.NET version you want your applications to use, especially if you install a newer version of ODP.NET on your system.

    General Installation
    If you have one Oracle client already installed, ensure that you don't overwrite this previously installed Oracle Home when you install the next Oracle client. Upon reaching the Oracle client install's "File Locations" screen, enter in a directory name different from the previous Oracle client installation.

    Automatic Switching Between Oracle Homes with No Setup Required
    In ODP.NET and higher, ODP.NET can run more than one active Oracle Home concurrently without requiring any special setup by the administrator.

    When ODP.NET is installed, the DLL search path will be based on the following order:
    1. i) directory of the application/executable
    2. ii) directory specified by HKEY_LOCAL_MACHINE\Software\Oracle\ODP.NET\\DllPath
    3. iii) directories specified by the PATH environment variable

    Upon an ODP.NET installation, the DllPath registry value of type REG_SZ will be set to the %ORACLE_HOME%\bin directory where the corresponding dependent DLLs are installed.

    Note that the DllPath registry value takes effect only on Windows XP, Windows Server 2003, and Windows Server 2003 R2. On Windows 2000, ODP.NET will simply rely on the application directory and PATH for loading dependent unmanaged DLLs.

    Installation for Relases Prior to ODP.NET
    The last Oracle Home you install will be the client your .NET applications will use. For example, if you installed the Oracle10 g Release 2 client last, this will be the client version all Oracle10 g applications on your system will use. The only exception is that applications using a different major Oracle client version will not use this latest installed client. For example, applications using the Oracle9 i and Oracle8 i clients will not use Oracle10 g client DLLs when it is installed. Those applications will still use the Oracle client it was using previously. Note that .NET policy files only dictate which .NET assemblies are used, not what Oracle client files are used.

    If you wish for applications using the same major Oracle client version to use different minor Oracle client versions (e.g. different versions of Oracle10 g client), you will need to do some additional configuration. Oracle uses the Windows System Path to determine which Oracle client files an application calls. You can read more about Windows' DLL search order and the System Path.

    Automatic Switching Between Oracle Homes for Relases Prior to ODP.NET
    Automatic switching among Oracle Homes is preferred when running multiple applications concurrently that require different client versions.

    In a client/server environment, where each application runs as a separate process, it is possible to specify a different System Path for each concurrently running application. Every executable or Windows shortcut can be given a separate Oracle Home working directory in which it will load its Oracle client files from. Alternatively, a batch file that sets the application's System Path can be run prior to loading the ODP.NET application. Thus, each application can retain its own System Path with its own Oracle client. This allows each application to upgrade or patch its own Oracle client independently without affecting other Oracle client applications.

    Many Oracle applications run on Microsoft Internet Information Services (IIS). Previously, IIS was a single process application without the ability to assign a different System Path to each running web application using the same IIS instance. With IIS 6 on Windows Server 2003, IIS supports multiple processes for the same instance. Since each application has its own IIS process, each web application can be assigned a different System Path directory with its own Oracle Home.

    Microsoft documentation provides information on IIS worker process isolation and application pools.

    To set up multiple active Oracle Homes running concurrently on the same IIS server:

    1. 1) Run IIS 6 in worker process isolation mode on Windows Server 2003
    2. 2) Deploy one version of the Oracle Client to one application pool and the second version to another application pool. For example, you can have Oracle Client and ODP.NET be used by one application pool. And Oracle Client and ODP.NET can be employed by another application pool. You won't be able to use two active Oracle Homes in the same application pool. Each active Oracle Home must be in a different pool.
    3. 3) Set the DLL directory for each worker process to use the appropriate Oracle Home client directory. To do this, within each ASP.NET application, call SetDllDirectory(directory_name) early in the application lifecycle before any Oracle DLLs are called. The SetDllDirectory input variable is the Oracle Home bin directory of the ODP.NET version used. Note: SetDllDirectory is an unmanaged call.

    Manually Switching between Active Oracle Homes
    You can manually switch which Oracle client version your applications use through the Oracle Home Selector. The Oracle Home Selector changes your System Path settings so that the Oracle client you specify is the one used by applications on your system that share the same major Oracle client version. Once changed, any newly launched Oracle client applications will use this new Home. Already running applications will continue to use the Oracle Home they had been using before.

  • I get an error: "Unable to load DLL (OraOps.dll)". How do I fix this?

    First, ensure the OraOps.dll file is in your Oracle bin directory (e.g. d:\oracle\ora92\bin\). Next, check that your Oracle bin directory is in the Windows system path. If either of these are not present, re-install ODP.NET. Depending on the application, you may have to restart the application (e.g. Windows Service) or reboot the computer (e.g. ODP.NET install makes changes to the PATH) for ODP.NET installation to be complete. If your ODP.NET installation is still not working, you may be running into this problem.

  • I want to use the Oracle9 i Release 2 version of OraMTS with an Oracle8 i database. I get a "No error information available: XACT_E_NOENLIST(0x8004D00A)" error when running an application using OraMTS.

    These are two known issues with OraMTS. These problems can be resolved if you upgrade to OraMTS version or higher.

ODP.NET and Other Oracle Providers for .NET

  • Are ODP.NET and Microsoft .NET Framework Data Provider for Oracle the same product?

    No, these are two separate products. Both provide data access to the Oracle database. However, ODP.NET is developed by Oracle and provides more functionality and faster performance than the Microsoft .NET Framework Data Provider for Oracle. Oracle recommends you use ODP.NET.

  • Which .NET data access driver should I use among ODP.NET, Microsoft .NET Framework Data Provider for Oracle, OLE DB .NET, and ODBC .NET?

    ODP.NET offers more functionality and better performance over the Microsoft .NET Framework Data Provider for Oracle, OLE DB .NET, and OLE DB .NET.

  • I bundle ODP.NET with an application I've built, which I want to distribute or sell. Does Oracle charge licensing fees for this?

    In most cases, Oracle does not charge any fees for distributing the Oracle client nor ODP.NET with a third-party application. However, it is best to consult the licensing agreement from which you acquired rights to the Oracle software. If you purchased Oracle licenses directly from Oracle, consult your Oracle licensing contract or your Oracle sales representative. If you downloaded ODP.NET from OTN, consult the licensing agreement that you agreed to prior to downloading the software.