Connect to CouchDB Data in JRuby

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

Configure a JDBC Connection to CouchDB 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 CouchDB\lib).

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

Set the following to connect:

• Url: The Url of your instance. For example: http://localhost:5984
• User The Apache CouchDB user account used to authenticate.
• Password The Apache CouchDB password associated with the authenticating user.

Built-in Connection String Designer

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

java -jar cdata.jdbc.apachecouchdb.jar

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

Below is a typical JDBC connection string for CouchDB:

jdbc:apachecouchdb:Url=http://localhost:5984;User=abc123;Password=abcdef;

Create a JRuby App with Connectivity to CouchDB Data

Create a new Ruby file (for example: ApacheCouchDBSelect.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 CouchDB 2018/lib/cdata.jdbc.apachecouchdb.jar'

url = "jdbc:apachecouchdb:Url=http://localhost:5984;User=abc123;Password=abcdef;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT MovieRuntime, MovieRating FROM Movies")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

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

jruby -S ApacheCouchDBSelect.rb

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