Deleting Data From Oracle Database in Python

Summary: in this tutorial, you will learn how to use the Python cx_Oracle API to delete data from a table.

To delete data from a table, you use the following steps:

• First, connect to the Oracle Database by creating a new Connection object.
• Second, create a new Cursor object from the Connection object by calling the Connection.Cursor() method.
• Third, execute a DELETE statement by calling the Cursor.execute() method.
• Fourth, call the Connection.commit() method to apply the changes to the database. If you forget to call the Connection.commit() method, you will see that the change will not take effect.
• Finally, release the Cursor and Connection objects by calling the Cursor.close() and Connection.close() method respectively. You can also use the with block to release these objects automatically.

The following code illustrates how to delete a row from the billing_headers table based on a specific billing number.

import oracledb
from connect import connect
import logging


def delete(billing_no: int) -> bool:

    sql = '''DELETE FROM billing_headers WHERE billing_no = :billing_no'''
             
    try:
        with connect() as connection:
            with connection.cursor() as cursor:
                params = {
                    'billing_no': billing_no                    
                }
                cursor.execute(sql, params)
                connection.commit()
                return True
    except oracledb.Error as e:
        error_message = f"Oracle database error during billing deletion for billing_no  {billing_no}: {e}"
        logging.error(error_message)
        raise
    except Exception as e:
        error_message = f"An unexpected error occurred during billing deletion for billing_no {billing_no}: {e}"
        logging.critical(error_message) 
        raise


if __name__ == '__main__':
    delete(1)Code language: Python (python)

Here are the contents of the billing_headers table after executing the program:

SELECT * FROM billing_headers;Code language: Python (python)

As you can see clearly from the output, the row whose billing_no is 1 has been removed. It means that the program works as expected.

In this tutorial, you have learned how to use the python-oracledb API to delete data in a table.