Example: Change values with a statement through another statement's cursor

import java.sql.*;

public class UsingPositionedUpdate {
    public Connection connection = null;
    public static void main(java.lang.String[] args) {

        UsingPositionedUpdate test = new UsingPositionedUpdate();

        test.setup();
        test.displayTable();

        test.run();
        test.displayTable();

        test.cleanup();
    }



/**
Handle all the required setup work.
**/
    public void setup() {
        try {
            // Register the JDBC driver.
            Class.forName("com.ibm.db2.jdbc.app.DB2Driver");

            connection = DriverManager.getConnection("jdbc:db2:*local");

            Statement s = connection.createStatement();
            try {
                s.executeUpdate("DROP TABLE CUJOSQL.WHERECUREX");
            } catch (SQLException e) {
                // Ignore problems here.
            }

            s.executeUpdate("CREATE TABLE CUJOSQL.WHERECUREX ( " + 
                            "COL_IND INT, COL_VALUE CHAR(20)) ");

            for (int i = 1; i <= 10; i++) {
                s.executeUpdate("INSERT INTO CUJOSQL.WHERECUREX VALUES(" + i + ", 'FIRST')");
            }

            s.close();

        } catch (Exception e) {
            System.out.println("Caught exception: " + e.getMessage());
            e.printStackTrace();
        }
    }


/**
In this section, all the code to perform the testing should
be added. If only one connection to the database is required, 
the global variable 'connection' can be used.
**/
    public void run() {
        try {
            Statement stmt1 = connection.createStatement();

            // Update each value using next().
            stmt1.setCursorName("CUJO");
            ResultSet rs = stmt1.executeQuery ("SELECT * FROM CUJOSQL.WHERECUREX " +
                                               "FOR UPDATE OF COL_VALUE");

            System.out.println("Cursor name is " + rs.getCursorName());

            PreparedStatement stmt2 = connection.prepareStatement ("UPDATE "
                                                                   + " CUJOSQL.WHERECUREX 
                                                                       SET COL_VALUE = 'CHANGED' 
                                                                       WHERE CURRENT OF "
                                                                   + rs.getCursorName ());


            // Loop through the ResultSet and update every other entry.
            while (rs.next ()) {
                if (rs.next())
                    stmt2.execute ();
            }


            // Clean up the resources after they have been used.
            rs.close ();
            stmt2.close ();


        } catch (Exception e) {
            System.out.println("Caught exception: ");
            e.printStackTrace();
        }
    }



/**
In this section, put all clean-up work for testing.
**/   
    public void cleanup() {
        try {
            // Close the global connection opened in setup().
            connection.close();

        } catch (Exception e) {
            System.out.println("Caught exception: ");
            e.printStackTrace();
        }
    }



/**
Display the contents of the table.
**/
    public void displayTable() 
    {
        try {
            Statement s = connection.createStatement();
            ResultSet rs = s.executeQuery ("SELECT * FROM CUJOSQL.WHERECUREX");

            while (rs.next ()) {
                System.out.println("Index " + rs.getInt(1) + " value " + rs.getString(2));
            }

            rs.close ();
            s.close();
            System.out.println("-----------------------------------------");
        } catch (Exception e) {
            System.out.println("Caught exception: ");
            e.printStackTrace();
        }
    }
}