drop table tst1;
drop table tst2;

create table tst1 as
select level as id, level+1 as id2,  mod(level,10) as fid, lpad('*', level, '*') as pad from dual connect by level <= 100;

create table tst2 as
select level as id, lpad('*', level, '*') as name from dual connect by level <= 10;


ALTER TABLE tst1 ADD CONSTRAINT pk_tst1 PRIMARY KEY (id) USING INDEX;
ALTER TABLE tst2 ADD CONSTRAINT pk_tst2 PRIMARY KEY (id) USING INDEX;

alter table tst1 add
CONSTRAINT tstfk FOREIGN KEY (fid)
                  REFERENCES tst2 (id) ON DELETE CASCADE ENABLE NOVALIDATE;
                  
create index tst1_fk on tst1(fid);

insert into tst2 select -1 as id, ' ' as pad from dual;
1 row inserted.

truncate table tst1;
ORA-00054: ресурс занят и задано его получение с параметром NOWAIT, либо истекло время ожидания
00054. 00000 -  "resource busy and acquire with NOWAIT specified or timeout expired"