IBM i (AS400) DB2 is a powerful database often used in enterprise applications. If you need to connect to it remotely using Python, the pyodbc module provides an easy way to establish a connection and execute SQL queries.

In this blog, we'll walk through the steps to connect to IBM i DB2 using pyodbc, including installing dependencies, setting up the connection string, and executing queries.

Prerequisites

Before proceeding, ensure you have the following:

• Access to an IBM i (AS400) system running DB2.
• An IBM i ODBC driver installed on your system.
• Python installed (preferably Python 3).
• The pyodbc module installed in your Python environment.

Step 1: Install Required Packages

First, install the pyodbc module if you haven’t already:

pip install pyodbc

Step 2: Install and Configure the IBM i ODBC Driver

You need to install the IBM i Access ODBC driver. If you haven't installed it yet, download it from IBM's official website and configure the ODBC Data Source.

• On Windows, open ODBC Data Sources (64-bit).
• Under the "System DSN" tab, add a new data source.
• Select "IBM i Access ODBC Driver" and configure it with your IBM i system details.

Alternatively, you can directly specify the driver in your Python script.

Step 3: Connect to IBM i DB2 using Python

Here’s a sample Python script to connect to IBM i DB2 using pyodbc:

import pyodbc
# Define connection parameters
conn_str = (
    "DRIVER={IBMi Access ODBC Driver};"
    "SYSTEM=your_ibm_i_host;"
    "UID=your_username;"
    "PWD=your_password;"
)
try:
    # Establish connection
    conn = pyodbc.connect(conn_str)
    cursor = conn.cursor()
    print("Connected to IBMi DB2 successfully!")

    # Execute a sample query
    cursor.execute("SELECT * FROM your_schema.your_table FETCH FIRST 10 ROWS ONLY")
    rows = cursor.fetchall()
    
    for row in rows:
        print(row)
    
    # Close connection
    cursor.close()
    conn.close()
    print("Connection closed.")
except Exception as e:
    print("Error connecting to IBMi DB2:", e)

Step 4: Run the Python Script

Save the script as ibmi_db2_connect.py and run it:

python ibmi_db2_connect.py

If everything is configured correctly, you should see the retrieved rows printed on the console.

Troubleshooting

If you encounter issues, consider the following:

• Verify that the IBM i ODBC driver is installed and configured correctly.
• Ensure that your system can reach the IBM i host (check firewall settings and network connectivity).
• Double-check your username and password.
• Run pyodbc.drivers() in Python to list available drivers and confirm the correct driver name.

Conclusion

Connecting to IBM i (AS400) DB2 using Python and pyodbc is straightforward once you set up the correct ODBC driver and connection string. This approach allows you to integrate IBM i DB2 with modern Python applications for data processing and automation.