cx_Oracle: ImportError: DLL load failed: This application has failed

Question

Here\'s what I did:

1. I\'m on Windows XP SP3
2. I already had Python 2.7.1 installed.
3. I downloaded instantclient-basic-nt-11.2.0.3.0.zip

Answer 1

If you're using conda as a package manager, one way to overcome the DLL issue it to install oracle-instantclient by doing a conda install oracle-instantclient. This fixed the dependency which I couldn't fix by manually installing Oracle's instant-client.

Answer 2

I know this is an old post, but I had this problem today and none of the solutions worked. I figure this could work for others with the same problem as of now.

Python version : 2.7.15 (64 bits) cx_Oracle version : 6.4.1 Oracle Instant Client : 18.3

I kept getting the following error even though I followed evry steps in the correct order :

cx_Oracle.DatabaseError: DPI-1047: Oracle Client library cannot be loaded

I solved it by downgrading my Oracle Instant Client version to 12.1

Answer 3

I am using python35 64 bit and oracle express on win 7 (64 bit). I installed cx_Oracle using pip3 (pip3 install cx_Oracle) instead of downloading the installer from pypi.

I faced the same problem.

I solved it by following above guidelines, but instead of 32 bit client, I downloaded the 64 bit version of the instant client (instantclient-basic-windows.x64-11.2.0.4.0.zip) from http://www.oracle.com/technetwork/topics/winx64soft-089540.html.

I then extracted it to c:\oraclexe. And added these environment variables

set ORACLE_BASE=C:\oraclexe
set ORACLE_HOME=C:\oraclexe\app\oracle\product\11.2.0\server
set PATH=C:\oraclexe\instantclient_11_2;%PATH%

And ran my django migrate commands:
python manage.py migrate

It worked excellent

Answer 4

As is the second time I came to this question, I feel the need to post what I did:

I'm using:

• Win 8 64 bits
• Python 2.7

I had no success installing Python and cx_Oracle 64 bits.

It only worked when I tried 32 bits versions and followed @rob answer instructions

Answer 5

Had this issue also, and it seems importing cx_Oracle (at least as of 5.1.2) will fail (with the same error) if you have any invalid/unreachable UNC paths in front of Oracle in the PATH environment variable.

Fixing the UNC path (which was unrelated to Oracle) resolved the problem.

Answer 6

I had same issue with DLL load failed on my Windows machine. installed oracle client, set variables, ran cx_Oracle-5.1.3-11g.win32-py2.7.exe file.

however when I installed cx_Oracle with easy_setup it fixed the problem.

C:\Python27\Scripts\easy_install.exe cx_Oracle-5.1.3-11g.win32-py2.7.exe