The VoltDB driver is a standard class within the VoltDB software jar. To load the driver you use the Class.forName method to load the class org.voltdb.jdbc.Driver.

Once the driver is loaded, you create a connection to a running VoltDB database server by constructing a JDBC url using the "jdbc:" protocol, followed by "voltdb://", the server name, a colon, and the port number. In other words, the complete JDBC connection url is "jdbc:voltdb://{server}:{port}". To connect to multiple nodes in the cluster, use a comma separated list of server names and port numbers after the "jdbc:voltdb://" prefix.

For example, the following code loads the VoltDB JDBC driver and connects to the servers svr1 and svr2 using the default client port:

Class.forName("org.voltdb.jdbc.Driver");
Connection c = DriverManager.getConnection(
     "jdbc:voltdb://svr1:21212,svr2:21212");

Once the connection is made, you use the standard JDBC classes and methods to access the database. (See the JDBC documentation at http://download.oracle.com/​javase/6/docs/​technotes/​guides/jdbc for details.) Note, however, when running the JDBC application, you must make sure both the VoltDB software jar and the Guava library are in the Java classpath. Guava is a third party library that is shipped as part of the VoltDB kit in the /lib directory. Unless you include both components in the classpath, your application will not be able to find and load the necessary driver class.

The following is a complete example that uses JDBC to access the Hello World tutorial that comes with the VoltDB software in the subdirectory /doc/tutorials/helloworld. The JDBC demo program executes both an ad hoc query and a call to the VoltDB stored procedure, Select.

import java.sql.*;
import java.io.*;

public class JdbcDemo {

    public static void main(String[] args) {
 
        String driver = "org.voltdb.jdbc.Driver";
        String url = "jdbc:voltdb://localhost:21212";
        String sql = "SELECT dialect FROM helloworld";
        
        try {
                // Load driver. Create connection.
            Class.forName(driver);
            Connection conn = DriverManager.getConnection(url);
            
                // create a statement
            Statement query = conn.createStatement();
            ResultSet results = query.executeQuery(sql);
            while (results.next()) {
                System.out.println("Language is " + results.getString(1));
            }
            
                // call a stored procedure
            CallableStatement proc = conn.prepareCall("{call Select(?)}");
            proc.setString(1, "French");
            results = proc.executeQuery();
            while (results.next()) {
                System.out.printf("%s, %s!\n", results.getString(1), 
                                               results.getString(2));
            }
            
                 //Close statements, connections, etc.
            query.close(); 
            proc.close();
            results.close();
            conn.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}