In this post I will simply show how to connect to an Oracle database using Python 3 in an Oracle Linux 7.6 OS. One of the things that you have to do is to install Python in your OS. By default, Oracle Linux 7.6 comes with Python 7.6 but from 7.7 ownwards it comes with the version Python 3. If you wish to install the Python 3 in your system I do recommend you to take a look at one of my blog posts about this topic: “Installing Python 3 on Oracle Linux 7.6” https://www.techdatabasket.com/2020/06/02/installing-python-3-on-oracle-linux-7-6/ . After that you will have Python in the version that you wish, the next step is to install the module cx_Oracle that according from the Oracle Python Yum documentation “… is a module that enables access to Oracle Databases and conforms to the Python database API specification”. So to perform the installation from Pypi (https://pypi.org/project/cx-Oracle/) you should execute the command “python3 -m pip install cx_Oracle –upgrade” as below: (supposing that in this OS we have already Python 3 installed):
oraclelinux7] python3 -m pip install cx_Oracle --upgrade
Collecting cx_Oracle
Using cached https://files.pythonhosted.org/packages/d5/15/d38862a4bd0e18d8ef2a3c98f39e743b8951ec5efd8bc63e75db04b9bc31/cx_Oracle-7.3.0-cp36-cp36m-manylinux1_x86_64.whl
Installing collected packages: cx-Oracle
Successfully installed cx-Oracle-7.3.0
The next step is to install the Oracle Instant client. To be able to perform the Oracle instant client you can either perform the installation using the zip files or the RPM files. Following the 2 examples below:
Oracle Instant Client Zip Files
https://www.oracle.com/ae/database/technologies/instant-client/linux-x86-64-downloads.html
Oracle Instant Client RPMs
oraclelinux7]# yum install oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm Loaded plugins: langpacks, ulninfo Examining oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm: oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64 Marking oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm to be installed Resolving Dependencies --> Running transaction check ---> Package oracle-instantclient12.1-basic.x86_64 0:12.1.0.2.0-1 will be installed --> Finished Dependency Resolution Dependencies Resolved ============================================================================================================================================================================================================ Package Arch Version Repository Size ============================================================================================================================================================================================================ Installing: oracle-instantclient12.1-basic x86_64 12.1.0.2.0-1 /oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64 185 M Transaction Summary ============================================================================================================================================================================================================ Install 1 Package Total size: 185 M Installed size: 185 M Is this ok [y/d/N]: y Downloading packages: Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64 1/1 Verifying : oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64 1/1 Installed: oracle-instantclient12.1-basic.x86_64 0:12.1.0.2.0-1 Complete!
Now that you have the Oracle instant client installed and the Oracle cx_Oracle module, it’s time to create the script to connect to the Oracle database.
The script below is a totally educational example in a Productive environment you would never let the password of a user written in a script. As a matter of fact, the example here is performed in an Oracle Database 12cR1 that is a CDB database plus in a Oracle Linux 76.
So here is the description of the script:
oraclelinux7]$ cat myconnectdb.py
from __future__ import print_function
import cx_Oracle
# Connect as user "c##techdatabasket" with password "oraclexample123" to the "pythondb" service running on this computer. (Here I am saying that the user c##techdatabasket will connect to the password "oraclexample123" on the server "oraclelinux7" connecting to the service name "pythondb.localdomain" which connects to a database named "pythondb".
connection = cx_Oracle.connect("c##techdatabasket", "oraclexample123", "oraclelinux7/pythondb.localdomain")
cursor = connection.cursor()
##Here I want to know how many users exist in my Oracle Database
cursor.execute(
'SELECT count(*) from all_users')
for value in cursor:
print("Values:", value)
After finished the script is executed as below:
oraclelinux7]$ python3 myconnectdb.py Values: (36,)
So this is a simple explanation about how to connect to an Oracle Database using Python. If you want to check other scripts stay tuned at my GitHub channel: https://github.com/brunorsreis/oraclepython
Hi! I am Bruno, a Brazilian born and bred. Former Oracle ACE, Computer Scientist, MSc in Data Science, over ten years of experience in companies such as IBM, Epico Tech, and Playtech based in three different countries (Brazil, Hungary, and Sweden) and joined projects remotely in many others. I am super excited to show you my interest in Databases, Cloud, Data Science, Data Engineering, Bigdata, AI, Programming, Software Engineering, and data in general.
(Continue reading)