Tag: cx_oracle

Setting up a Python 2.7.6 Virtual Env for Python development

~ rajeevramdas@aol.com ~ Leave a comment

Python is an excellent language to learn, for DBA’s who want to automate all the repetitive tasks, they need to perform. Once you start using python it is likely that you want to setup multiple environments with different versions of Python and libraries, based on the project you are working on. Virtualenv is a tool to create isolated python environments.

Below are the steps that i followed, to install a brand new working Python 2.7.6 environment with the following packages.

 
           SQLAlchemy    - Object Relational Mapper and SQL Toolkit for Python
           numpy         - Fundamental package for scientific computing
           matplotlib    - Python 2D plotting library
           ipython       - Interactive Python Shell
           pandas        - Python Data Analysis Library 
           Flask         - An easy to use Python Lightweight Micro Framework

This installation is performed on Ubuntu Linux, and i have already installed the libsqlite3-dev package and the oracle instant client.

Install Python 2.7.6

Download Python-2.7.6.tgz from http://www.python.org/getit

Install python 2.7.6 to your directory of choice.

		tar -xvf Python-2.7.6.tgz
		cd Python-2.7.6/

		./configure --prefix=/u01/Rk/Apps/Python/Python276
		make
		make install

Now you have python 2.7.6 installed into the /u01/Rk/Apps/Python/Python276 directory. (You will have a python binary in /u01/Rk/Apps/Python/Python276/bin)

Download virtualenv

curl -O https://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.11.1.tar.gz

Install virtualenv

tar -xzvf virtualenv-1.11.1.tar.gz
cd virtualenv-1.11.1/
/u01/Rk/Apps/Python/Python276/bin/python virtualenv.py /u01/Rk/Apps/Python/p276env1

Activate the virtualenv

           . /u01/Rk/Apps/Python/p276env1/bin/activate

Install the additional Python Modules you need

	   pip install SQLAlchemy
	   pip install numpy
	   pip install matplotlib
	   pip install ipython
	   pip install pyzmq
	   pip install tornado
	   pip install jinja2
	   pip install pandas
	   pip install Flask
	   pip install Flask-SQLAlchemy

Install cx_Oracle

Ensure that the oracle instant client is installed, and the environment variables ORACLE_HOME and LD_LIBRARY_PATH are setup correctly.

Download cx_Oracle (a python extension module that allows access to oracle.) source from from http://cx-oracle.sourceforge.net/

tar -xzvf cx_Oracle-5.1.2.tar.gz
cd  cx_Oracle-5.1.2/
python setup.py install

Setup an alias (In your .bash_profile) to simplify invoking the virtualenv every time you want to use it.

alias p276env1='. /u01/Rk/Apps/Python/p276env1/bin/activate'

Now, anytime you want to execute a python program in this environment, you can invoke the Linux command line and

p276env1
python

Using Python 3

~ rajeevramdas@aol.com ~ Leave a comment

I have been writing some python scripts for awr analysis and trending. Since python 2.7 is no longer being enhanced, i have now switched to using python 3. Lot of python applications and frameworks still does not support python 3 (Notably the Django framework). Good news is that cx_oracle works with python 3.

The steps to install cx_oracle with python 3 are very similar to the steps that i had outlined in my previous post on installing cx_oracle with python 2.7.

The difference is that

– You have to first install python3 and python3-dev (On ubuntu, you can just use the ubuntu software center to do this)

– Then download the cx_oracle 5.1.1 source code only tar ball from http://cx-oracle.sourceforge.net/

– login as root, untar the tar file, cd to the cx_Oracle-5.1.1 directory

– Then run /usr/bin/python3 setup.py install

That does it and now oracle connectivity is in place.

I’ve also been using the matplotlib library along with Python to plot graphs with the awr and oswatcher data files. matplotlib also works with python 3.

– You have to first install libpng, libpng-dev, libfreetype6, libfreetype6-dev (Use the ubuntu software center)

– Download the numpy source code tar ball.

– Extract the tar file, login as root, cd to the directory and run /usr/bin/python3 setup.py install

– Installing matplotlib Ref :

– Download the matplotlib source code tar file

– Login as root, cd to the directory

– /usr/bin/python3 setup.py build

– /usr/bin/python3 setup.py install

Now you should have matplotlib working with python3

Enjoy your python scripting


Installing cx-oracle with 11.2.0.2 on ubuntu

~ rajeevramdas@aol.com ~ Leave a comment

cx_Oracle is a Python extension module that allows access to Oracle databases and conforms to the Python database API specification. Below are the steps i used to setup cx_Oracle, with 11.2.0.2, python 2.6 on Ubuntu 10.04 (Lucid Lynx).

1) Installed Oracle 11.2.0.2 Enterprise Edition on Ubuntu (You can also configure this by just installing the 11.2.0.2 instant client too)

2) Download cx_Oracle Source code from http://cx-oracle.sourceforge.net/

3) Install python-dev on ubuntu (Or else you will get compile errors (Like file Python.h not found) when you try to install cx-oracle)

– sudo apt-get install python-dev

4) Login as root

5) export ORACLE_HOME=/u01/11gr2/db_1;export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH

6) cd <dir-where-cx-oracle-untarred>/cx_Oracle-5.0.4

7) python setup.py install

Once it is installed you can run the sample program from http://wiki.oracle.com/page/Python to make sure it works.