sbHistoryDeleteSql.append("delete from " +
getHarvestingHistoryTableName() + " ");
sbHistoryDeleteSql.append("where HARVEST_ID = ?");
// establish the connection
ManagedConnection mc = returnConnection();
con = mc.getJdbcConnection();
autoCommit = con.getAutoCommit();
con.setAutoCommit(false);
stJobsDelete = con.prepareStatement(sbJobsDeleteSql.toString());
stCompletedJobsDelete = con.prepareStatement(sbCompletedJobsDeleteSql.