deferrable constraint

create table cons_deferrable_pk_tab (
  a number,
  b varchar2(10),
  c number not null deferrable,
  d date,
  primary key (a, b) deferrable
);

create table cons_deferrable_fk_tab (
  z,
  y,
  x varchar2(10),
  foreign key (z,y) references cons_deferrable_pk_tab deferrable
);

insert into cons_deferrable_fk_tab values (1, 'one', 'foo');

set constraints all deferred;

insert into cons_deferrable_fk_tab values (1, 'one', 'foo');