Connect to Neo4J Data in JRuby

JRuby is a high-performance, stable, fully threaded Java implementation of the Ruby programming language. The CData JDBC Driver for Neo4J makes it easy to integrate connectivity to live Neo4J data in JRuby. This article shows how to create a simple JRuby app that connects to Neo4J data, executes a query, and displays the results.

Configure a JDBC Connection to Neo4J 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 Neo4J\lib).

JRuby natively supports JDBC, so you can easily connect to Neo4J and execute SQL queries. Initialize the JDBC connection with the getConnection function of the java.sql.DriverManager class.

To connect to Neo4j, set the following connection properties:

• Server: The server hosting the Neo4j instance.
• Port: The port on which the Neo4j service is running. The provider connects to port 7474 by default.
• User: The username of the user using the Neo4j instance.
• Password: The password of the user using the Neo4j instance.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the Neo4J JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.neo4j.jar

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

Below is a typical JDBC connection string for Neo4J:

jdbc:neo4j:Server=localhost;Port=7474;User=my_user;Password=my_password;

Create a JRuby App with Connectivity to Neo4J Data

Create a new Ruby file (for example: Neo4jSelect.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 Neo4J 2018/lib/cdata.jdbc.neo4j.jar'

url = "jdbc:neo4j:Server=localhost;Port=7474;User=my_user;Password=my_password;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT CategoryId, CategoryName FROM ProductCategory")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

With the file completed, you are ready to display your Neo4J data with JRuby. To do so, simply run your file from the command line:

jruby -S Neo4jSelect.rb

Writing SQL-92 queries to Neo4J allows you to quickly and easily incorporate Neo4J data into your own JRuby applications. Download a free trial today!