Discover how a bimodal integration strategy can address the major data management challenges facing your organization today.
Get the Report →How to Connect to DB2 Data in Using Python: 6 Steps
Create Python applications on Linux/UNIX machines with connectivity to DB2 data. Leverage the pyodbc module for ODBC in Python.
The rich ecosystem of Python modules lets you get to work quicker and integrate your systems more effectively. With the CData Linux/UNIX ODBC Driver for DB2 and the pyodbc module, you can easily build DB2-connected Python applications. This article shows how to use the pyodbc built-in functions to connect to DB2 data, execute queries, and output the results.
How to Use the CData ODBC Drivers on UNIX/Linux
The CData ODBC Drivers are supported in various Red Hat-based and Debian-based systems, including Ubuntu, Debian, RHEL, CentOS, and Fedora. There are also several libraries and packages that are required, many of which may be installed by default, depending on your system. For more information on the supported versions of Linux operating systems and the required libraries, please refer to the "Getting Started" section in the help documentation (installed and found online).
1. Install the Driver Manager
Before installing the driver, check that your system has a driver manager. For this article, you will use unixODBC, a free and open source ODBC driver manager that is widely supported.
For Debian-based systems like Ubuntu, you can install unixODBC with the APT package manager:
$ sudo apt-get install unixodbc unixodbc-dev
For systems based on Red Hat Linux, you can install unixODBC with yum or dnf:
$ sudo yum install unixODBC unixODBC-devel
The unixODBC driver manager reads information about drivers from an odbcinst.ini file and about data sources from an odbc.ini file. You can determine the location of the configuration files on your system by entering the following command into a terminal:
$ odbcinst -j
The output of the command will display the locations of the configuration files for ODBC data sources and registered ODBC drivers. User data sources can only be accessed by the user account whose home folder the odbc.ini is located in. System data sources can be accessed by all users. Below is an example of the output of this command:
DRIVERS............: /etc/odbcinst.ini
SYSTEM DATA SOURCES: /etc/odbc.ini
FILE DATA SOURCES..: /etc/ODBCDataSources
USER DATA SOURCES..: /home/myuser/.odbc.ini
SQLULEN Size.......: 8
SQLLEN Size........: 8
SQLSETPOSIROW Size.: 8
2. Install the Driver
You can download the driver in standard package formats: the Debian .deb package format or the .rpm file format. Once you have downloaded the file, you can install the driver from the terminal.
The driver installer registers the driver with unixODBC and creates a system DSN, which can be used later in any tools or applications that support ODBC connectivity.
For Debian-based systems like Ubuntu, run the following command with sudo or as root:
$ dpkg -i /path/to/package.deb
For Red Hat systems and other systems that support .rpms, run the following command with sudo or as root:
$ rpm -i /path/to/package.rpm
Once the driver is installed, you can list the registered drivers and defined data sources using the unixODBC driver manager:
List the Registered Driver(s)
$ odbcinst -q -d
CData ODBC Driver for IBM DB2
...
List the Defined Data Source(s)
$ odbcinst -q -s
CData DB2 Source
...
To use the CData ODBC Driver for IBM DB2 with unixODBC, ensure that the driver is configured to use UTF-16. To do so, edit the INI file for the driver (cdata.odbc.db2.ini), which can be found in the lib folder in the installation location (typically /opt/cdata/cdata-odbc-driver-for-db2), as follows:
cdata.odbc.db2.ini
...
[Driver]
DriverManagerEncoding = UTF-16
3. Modify the DSN
The driver installation predefines a system DSN. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties. Additionally, you can create user-specific DSNs that will not require root access to modify in $HOME/.odbc.ini.
Set the following properties to connect to DB2:
- Server: Set this to the name of the server running DB2.
- Port: Set this to the port the DB2 server is listening on.
- Database: Set this to the name of the DB2 database.
- User: Set this to the username of a user allowed to access the database.
- Password: Set this to the password of a user allowed to access the database.
You will also need to install the corresponding DB2 driver:
- Windows: Install the IBM Data Server Provider for .NET.
On Windows, installing the IBM Data Server Provider is sufficient, as the installation registers it in the machine.config.
- Java: Install the IBM Data Server Driver for JDBC.
In the Java version, place the IBM Data Server Driver JAR in the www\WEB-INF\lib\ folder for this application.
/etc/odbc.ini or $HOME/.odbc.ini
[CData DB2 Source]
Driver = CData ODBC Driver for IBM DB2
Description = My Description
Server = 10.0.1.2
Port = 50000
User = admin
Password = admin
Database = test
For specific information on using these configuration files, please refer to the help documentation (installed and found online).
You can follow the procedure below to install pyodbc and start accessing DB2 through Python objects.
4. Install pyodbc
You can use the pip utility to install the module:
pip install pyodbc
Be sure to import with the module with the following:
import pyodbc
5. Connect to DB2 Data
You can now connect with an ODBC connection string or a DSN. Below is the syntax for a connection string:
cnxn = pyodbc.connect('DRIVER={CData ODBC Driver for IBM DB2};Server=10.0.1.2;Port=50000;User=admin;Password=admin;Database=test;')
Below is the syntax for a DSN:
cnxn = pyodbc.connect('DSN=CData DB2 Sys;')
6. Execute SQL on DB2
Instantiate a Cursor and use the execute method of the Cursor class to execute any SQL statement.
cursor = cnxn.cursor()
Select
You can use fetchall, fetchone, and fetchmany to retrieve Rows returned from SELECT statements:
import pyodbc
cursor = cnxn.cursor()
cnxn = pyodbc.connect('DSN=CData DB2 Source;User=MyUser;Password=MyPassword')
cursor.execute("SELECT OrderName, Freight FROM Orders WHERE ShipCity = 'New York'")
rows = cursor.fetchall()
for row in rows:
print(row.OrderName, row.Freight)
You can provide parameterized queries in a sequence or in the argument list:
cursor.execute(
"SELECT OrderName, Freight
FROM Orders
WHERE ShipCity = ?", 'New York',1)
Insert
INSERT commands also use the execute method; however, you must subsequently call the commit method after an insert or you will lose your changes:
cursor.execute("INSERT INTO Orders (ShipCity) VALUES ('New York')")
cnxn.commit()
Update and Delete
As with an insert, you must also call commit after calling execute for an update or delete:
cursor.execute("UPDATE Orders SET ShipCity = 'New York'")
cnxn.commit()
Metadata Discovery
You can use the getinfo method to retrieve data such as information about the data source and the capabilities of the driver. The getinfo method passes through input to the ODBC SQLGetInfo method.
cnxn.getinfo(pyodbc.SQL_DATA_SOURCE_NAME)
You are now ready to build Python apps in Linux/UNIX environments with connectivity to DB2 data, using the CData ODBC Driver for IBM DB2.