delete cascade

test.sql

create table tst_t1 (
	id int not null primary key,
	name text
);

create table tst_a (
	id int not null primary key,
	t1id int references tst_t1 on delete cascade,
	name text
);

create table tst_b (
	id int not null primary key,
	aid int references tst_a on delete cascade,
	name text
);

create table tst_d (
	id int not null primary key,
	t1id int references tst_t1 on delete cascade,
	name text
);

create table tst_c (
	id int not null primary key,
	bid int references tst_b on delete cascade,
	did int references tst_d on delete restrict,
	name text
);

insert into tst_t1 (id, name) values (1, 'T1');
insert into tst_a (id, t1id, name) values (1, 1, 'A');
insert into tst_b (id, aid, name) values (1, 1, 'B');
insert into tst_d (id, t1id, name) values (1, 1, 'D');
insert into tst_c (id, bid, did, name) values (1, 1, 1, 'C');

delete from tst_t1 where id = 1;