Questão 582628

alter table Z

add constraint Z2 foreign key (a) references X;

alter table Z

add constraint Z2 foreign key (c) references X(a);

alter table Z

add constraint Z2 foreign key (e) references X;

alter table Z

add constraint Z2 foreign key (a,c) references X, Y;

alter table Z

add constraint Z2 foreign key (c) references X (b);