[Tutor] cx_Oracle and Pyinstaller

Bill Allen wallenpb at gmail.com
Thu Dec 11 01:42:38 CET 2014

I have had success with producing a single file executable from a Python
script that includes cx_Oracle.  Here are the details.  Hopefully this will
also help someone struggling to get this working.

OS was Windows 7 Pro 64 bit.

Python was 2.7.8 32 bit.

cx_Oracle-5.13 for 2.7


Python script oracle_connect.py, this was my program.

Oracle 11g instant client DLL files, OCI.dll and oraociei11.dll (OCI.dll
seems to stay constant from version to version of Oracle, but the other DLL
file's name will change with Oracle versions.)

A properly designed tnsnames.ora file.  This contains the necessary
connection information for your Oracle database.

A Pyinstaller-2.1 .spec file to make sure Pyinstaller did everything that
was needed to produce the single file .exe.  Pyinstaller-2.1 will not
automatically include both DLLs into the .exe without using a .spec file.
It does pick up the OCI.dll file automatically, but not oraociei11.dll.

First, I began by writing my Python script, which imports cx_Oracle, makes
the connection to the database, and does some work.  My working directory
was C:\Python27, so the script, two DLL files and .ora file were all placed
there.  Test the code to make sure that via the interpreter the script
interacted with the database correctly.

Second, I ran Pyinstaller-2.1 against the oracle_connect.py script without
the -F option (for single file .exe).  This created an oracle_connect.spec
file which I used as a template which was edited to include the needed

Third, I edited the oracle_connect.spec file (see bellow) to specify a
single file executable and to include the oraociei11.dll in the compilation
 The paths were specific to my installation environment and where I had
placed by Python source file and other files, adjust to match your
environment.  This oracle_connect.spec file I then placed in my
c:\Python27\PyInstaller-2.1 direcory.  Then I executed the following to
produce the single file executable.

C:\Python27\PyInstaller-2.1>..\python.exe .\pyinstaller.py

The resulting oracle_connect.exe may now be distributed without including
loose DLLs.  The only additional file needed is the tnsnames.ora file.
This cannot be compiled into the program and must reside in the same
location as the executable program.  It is a configuration file for the
communications parameters necessary to make the connection to the Oracle
database.  I include a sample of a tnsnames.ora file below.

oracle_connect.spec file contents:

# -*- mode: python -*-
a = Analysis(['..\\oracle_connect.py'],
pyz = PYZ(a.pure)
exe = EXE(pyz,
          a.binaries  +
          console=True )

Sample tnsnames.ora, values in <> are Oracle installation specific, contact
your local Oracle admin for the correct values to use.

# tnsnames.ora Network Configuration File

<Oracle instance name> =
      (ADDRESS = (PROTOCOL = TCP)(HOST = <FQDN or IP>)(PORT = <1521>))
      (SERVICE_NAME = <Oracle service name>)


--Bill Allen

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