declare
    object_exists exception;
    pragma exception_init (object_exists , -00955);
begin
	execute immediate 'ALTER TABLE PACOTE_FORMAPAGO
					   ADD CONSTRAINT FK_PACOTE_FORMAPAGO_NC FOREIGN KEY (NOTACREDITOVENDAPACOTE_ID)
					   REFERENCES NOTA_CREDITO_VENDA_PACOTE (NOTACREDITOVENDAPACOTE_ID)';
    exception when object_exists then null;
end;