Scrollable result sets

When you use a result set of type of type ResultSet.TYPE_SCROLL_INSENSITIVE, Derby materializes rows from the first one in the result set up to the one with the biggest row number as the rows are requested. The materialized rows will be backed to disk if necessary, to avoid excessive memory usage.

Insensitive result sets, in contrast to sensitive result sets, are insensitive to changes made by others on the rows which have been materialized. Derby allows updates of scrollable insensitive result sets, please see Visibilty of changes, which also explains visibility of own changes.

//autocommit does not have to be off because even if 
//we accidentally scroll past the last row, the implicit commit
//on the the statement will not close the result set because result sets
//are held over commit by default
conn.setAutoCommit(false);
Statement s4 = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, 
                                    ResultSet.CONCUR_READ_ONLY);
s4.execute("set schema 'SAMP'");
ResultSet scroller=s4.executeQuery(
    "SELECT sales_person, region, sales FROM sales " +
    "WHERE sales > 8 ORDER BY sales DESC");
if (scroller.first()) { // One row is now materialized
    System.out.println("The sales rep who sold the highest number" +
                       " of sales is " +
                       scroller.getString("SALES_PERSON"));
} else {
    System.out.println("There are no rows.");
}
scroller.beforeFirst();
scroller.afterLast();   // By calling afterlast(), all rows will be materialized
scroller.absolute(3);
if (!scroller.isAfterLast()) {
    System.out.println("The employee with the third highest number " +
                       "of sales is " +
                       scroller.getString("SALES_PERSON") + ", with " +
                       scroller.getInt("SALES") + " sales");
}
if (scroller.isLast()) {
    System.out.println("There are only three rows.");
}
if (scroller.last()) {
    System.out.println("The least highest number " +
                       "of sales of the top three sales is: " +
                       scroller.getInt("SALES"));
}
scroller.close();
s4.close();
conn.commit()
conn.close();
System.out.println("Closed connection");