--- In firebird-support@yahoogroups.com, "javaguru_uk"
<fidel.viegas@...> wrote:

> This should do the trick:
>
> ALTER TABLE DATA ADD CONSTRAINT FK_DATA_SENSOR_MAC
> FOREIGN KEY (MAC) REFERENCES SENSOR(MAC)
> ON UPDATE NO ACTION ON DELETE CASCADE;
>

I am assuming you have removed the constraint before creating a new
one. Some people forget about this. So, just a reminder.