Hi:

I am trying to reset a given ResultSet back to the first record, so that I could iterate through its records one more time, after it's already been done once. So, my code does something like this (it's pseudo-code, and in the real application these two passes are done in different parts of the application):

// get ResultSet
final ResultSet resultSet = ((PreparedStatement) m_statement).executeQuery();
final int columnCount = resultSet.getMetaData().getColumnCount();
// First Pass through the data
while (resultSet.next()) {
        for (int i = 1; i <= columnCount; i++) {
                if (resultSet.wasNull()) {
                        doSomethingWithNULL();
                } else {
                        doSomethingWithObject(resultSet.getObject(i));
                }
        }
}
// Reset ResultSet - but it generates SQLException: The 'beforeFirst()' method is only allowed on scroll cursors
resultSet.beforeFirst();
// Second Pass through the data
while (resultSet.next()) {
        for (int i = 1; i <= columnCount; i++) {
                if (resultSet.wasNull()) {
                        doSomethingElseWithNULL();
                } else {
                        doSomethingElseWithObject(resultSet.getObject(i));
                }
        }
}


However, resultSet.beforeFirst() generates an exception:

java.sql.SQLException: The 'beforeFirst()' method is only allowed on scroll cursors.
        at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedResultSet.checkScrollCursor(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedResultSet.beforeFirst(Unknown Source)
Caused by: java.sql.SQLException: The 'beforeFirst()' method is only allowed on scroll cursors.
        at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
        ... 8 more

Could someone please help me out to understand what may be done incorrectly and what would be the right approach to enable two-pass logic through the RecordSet?

Thanks,

Pavel.



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