Hi
Very simple, by creating a foreign key constraint (if you use IBExpert, Constraints tab in table designer)

alter table CHILD_TABLE
add constraint FK_CONSTR
foreign key (PK_PARENT)
references PARENT_TABLE(ID_PARENT)
on delete CASCADE
on update CASCADE

>Hello,
>
>How can I create a referencial integrity in Firebird database?
>
>Thank you very much
>
>Adionei