I believe this will resolve open issues 126, 171, 181, 185, and 187

Dependency walker indicates that pyodbc.pyd depends on msvcr90.dll. It appears that this dependency is being satisfied by running inside of python.exe (which is linked against the same). When the dll version of the python interpreter is instead hosted by another process, the windows sxs configuration applies the msvcr90 dependency only to the python dll.

This means that, in general, pyodbc.pyd (and likely pyodbcconf.pyd) will be unusable in embedded python on windows unless the host application is linked against the appropriate version of the msvc runtimes.

Because of how SxS dlls work it does not suffice to simply drop the msvc runtime dlls into the dll search path, instead the correct version of the runtime must be installed to the system and referenced in the dll's manifest. (I believe trying to load the mvcr90 dll from the search path is the cause of the R6034 error in issue 181)

Since pyodbc works inside of python, it suffices to embed the python27.dll's manifest into the pyds. As a work-around this can be done directly to the pyd's by using the manifest tool (mt.exe - a freely available tool in the windows sdk) with the commands below. You will likely need to adjust the paths to suit your own needs.

mt.exe -inputresource:c:\windows\syswow64\python27.dll;#2 -outputresource:pyodbc.pyd;#2

mt.exe -inputresource:c:\windows\syswow64\python27.dll;#2 -outputresource:pyodbcconf.pyd;#2

Alternatively you can try extracting the manifest from python.exe by changing the inputresource argument to -inputresource:c:\python27\python.exe;#1. I have not tested importing the manifest from the exe but I expect that it works.

I should add that the pyd files can typically be found in your user-specific egg installation path or the lib\site-packages subdirectory of your python installation, depending on installation method.

I just tested this on my Windows 64bit with 32bit python. Then tryed to import pyodbc in gvim and it works :) Thanks

Great tip! The autocomplete when using scripts with pyodbc on vim "cream" on windows 32 bits is working Ok. Many Thanks :)

Thank you! This solution makes it possible to use pyodbc in Python apps running under mod_wsgi on Apache.

Thank you for the excellent description.

I am embedding Python 2.7 in a number of Windows services and they always work, but I would bet I'm using the exact same service pack level that was used to build Python 2.7. I am guessing that the other apps being embedded into, such as Apache, are at a different level.

The stupidity of Microsoft's design here can't be overstated. Fortunately they've removed this nonsense in VS 2010. Unfortunately they didn't back port it.

Since pyodbc can be built for Python 2.4-2.7 and 3.2+, I'll try copying the manifest from whatever version of python is being used to build pyodbc. I looked into mt.exe before, but I was pretty sure you were required to have the Windows SDK installed, which I hate to add to the prerequisites (though most people probably use prebuilt binaries).

any idea when you will have updated prebuilt binaries?

Great！It works. Thank you very much!

It looks like this is a solid fix, and I'd love to apply it, but I'm having trouble with the command. I'm a Linux guy, and the Windows command line frightens and confuses me. To make matters worse, I get different errors in different shells.

I posted a question on Stack Overflow with the details. I'd be immensely grateful to anyone who could point me in the right direction so I can get my app deployed.

http://stackoverflow.com/questions/10626807/correct-mt-exe-syntax-to-resolve-pyodbc-import-problems

Thanks for this solution. It saved the rest of hair on my head ;-) I was wondering why everything worked great with python 2.7.0.2/pyodbc 2.1.8 and did not with python 2.7.2.5/pyodbc 3.0.2 but only under apache/wsgi, from python console everything was OK. Thanks again

Thanks! Saved my day!