错误：ORA-02291：违反完整性约束（SYS.SYS_C004198）-找不到父键

Question

create table centralsupplies
(
wardnum int  references ward(wnum),
drugnum int references pharmasupplies(dnum),
quantity_required varchar(20),
staffnum int references staff(stnum),
regnum int unique,
dateord date,
daterec date,
primary key(wardnum,drugnum,staffnum)
);

insert into centralsupplies values(1,204,1000,125,300,DATE '2020-01-02',DATE '2020-01-12');

insert into centralsupplies values(2,203,980,124,301,DATE '2020-01-03',DATE '2020-01-09');

OUTPUT:insert into centralsupplies values(1,204,1000,125,300,DATE '2020-01-02',DATE '2020-01-12')

我如何插入此项？？