declare
    column_exists exception;
    pragma exception_init (column_exists , -01430);
begin
    execute immediate 'ALTER TABLE ORGAO_CANCELACION ADD(INDMULTATRANSFERENCIA NUMBER(1,0),
                                  INDDEVOLUCAOTRANSFERENCIA NUMBER(1,0),
                                  INDCOBRANCATRANSFERENCIA NUMBER(1,0))';
    exception when column_exists then null;
end;