Connect to DB2 Data in JRuby

JRuby is a high-performance, stable, fully threaded Java implementation of the Ruby programming language. The CData JDBC Driver for DB2 makes it easy to integrate connectivity to live DB2 data in JRuby. This article shows how to create a simple JRuby app that connects to DB2 data, executes a query, and displays the results.

Configure a JDBC Connection to DB2 Data

Before creating the app, note the installation location for the JAR file for the JDBC Driver (typically C:\Program Files\CData\CData JDBC Driver for DB2\lib).

JRuby natively supports JDBC, so you can easily connect to DB2 and execute SQL queries. Initialize the JDBC connection with the getConnection function of the java.sql.DriverManager class.

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.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the DB2 JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.db2.jar

Fill in the connection properties and copy the connection string to the clipboard.

Below is a typical JDBC connection string for DB2:

jdbc:db2:Server=10.0.1.2;Port=50000;User=admin;Password=admin;Database=test;

Create a JRuby App with Connectivity to DB2 Data

Create a new Ruby file (for example: DB2Select.rb) and open it in a text editor. Copy the following code into your file:

require 'java'
require 'rubygems'
require 'C:/Program Files/CData/CData JDBC Driver for DB2 2018/lib/cdata.jdbc.db2.jar'

url = "jdbc:db2:Server=10.0.1.2;Port=50000;User=admin;Password=admin;Database=test;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT OrderName, Freight FROM Orders")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

With the file completed, you are ready to display your DB2 data with JRuby. To do so, simply run your file from the command line:

jruby -S DB2Select.rb

Writing SQL-92 queries to DB2 allows you to quickly and easily incorporate DB2 data into your own JRuby applications. Download a free trial today!