protected void upgradeStructureFields() throws DotDataException {
try {
DotConnect dc=new DotConnect();
if(DbConnectionFactory.isOracle()) {
dc.executeStatement("alter table structure add expire_date_var varchar2(255)");
dc.executeStatement("alter table structure add publish_date_var varchar2(255)");
}
else {
dc.executeStatement("alter table structure add expire_date_var varchar(255)");
dc.executeStatement("alter table structure add publish_date_var varchar(255)");