I needed to read an Oracle DB from SQL Server, so I had to install the Oracle provider (ORAOLEDB.Oracle).

My machine:

System: Windows Server R2 2008 Enterprise, 64 bits (SP1).

RDMS: Microsoft SQL Server 2008 R2 (RTM) - 10.50.1600.1 (X64)

However, at the beginning I installed just the 64 bits ODAC version for Oracle provider but it did not work. Finally I got it done by installing the 32 bits version, just how is said here.

Then I need to replicate the installation in production, I don't want to install both if is not required, so, I want to know why I should use both.

  • I see no reason to use both. If the 64-bit didn't work, then that was the wrong one. It'It would be easy enough to test it, wouldn't it? BTW, it's not a matter of matching the address size of the OS, but of the app that actually uses the provider. And there is still several boat-loads of 32-bit MS software out there, even on 64-bit OSs.
    – EdStevens
    Commented Oct 6, 2017 at 22:15
  • Well, since it's a production server I don't have enough chance to test it, so I'd prefer the install the correct one to avoid any issue.
    – Jamo
    Commented Oct 6, 2017 at 22:26

2 Answers 2


As alluded to in the question you linked to, some SQL Server tools/applications are 32-bit only. The main SQL Server application (sqlservr.exe) is 64-bit (32-bit may still be available as well, not certain about that for the latest versions); however, some of the supporting tools, perhaps most notable SQL Server Management Studio (ssms.exe), are only available as 32-bit applications.

If you want to install both versions, this should be sufficient reason.

If you want to find out if you can avoid installing the 64-bit version, all I can suggest is uninstalling that version from your development environment, and confirming whether or not everything still works as expected (including SSMS, and any other applications you use). If everything works fine, you can probably skip installing the 64-bit version in production. If you have problems, assume you need both versions.


In some cases your machine runs 32-bit and 64-bit applications, especially on a development machine.

A 32-bit application (include drivers like ODBC, OLEDB, etc.) can use only the 32-bit Oracle Client, resp. 64-bit applications require the 64-bit Oracle Client. Some applications are not available for 64 bit or not very common, e.g. MS Office which may utilize ODBC.

If you run only 32-bit applications then there is no need to install also an 64-bit Oracle Client.

However, if you have to use both I recommend this instruction in order to use 32 and 64 bit applications seamless at the same time.

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