外键值没有匹配的主键值

Question

为什么我会

Error report:
SQL Error: ORA-02291: integrity constraint (FAUZI.NIL_NIM_FK) violated - parent key not found
02291. 00000 - "integrity constraint (%s.%s) violated - parent key not found"
*Cause:    A foreign key value has no matching primary key value.
*Action:   Delete the foreign key or add a matching primary key. ?

这是数据库表的结构：

    alter table nilai
add
( 
constraint nil_kd_makul_fk foreign key(kd_makul) references 
makul(kd_makul),
constraint nil_nim_fk foreign key(nim) references mahasiswa(nim)
on delete cascade
)

插入makul

选择＆＃39; A1＆＃39;，＆＃39; Jarkom＆＃39;，4,4来自双重

联合所有

选择＆＃39; A2＆＃39;，＆＃39; Keamanan Data＆＃39;，3,5来自双重

联合所有

选择＆＃39; A3＆＃39;，＆＃39; Jarkom 2＆＃39;，4,4来自双重

/

NAMA                           JURUSAN                        TGL_LAHIR                 JK ALAMAT                         STATUS               NIM                  
------------------------------ ------------------------------ ------------------------- -- ------------------------------ -------------------- -------------------- 
mas mas                        SI                             21-01-1994                                                                       123                  
fauzi                          TI                             14-09-1991                                                                       124                  
zainn                          EKONOMI                        03-03-2014        

我得到错误，然后我写语法：

insert into nilai
    select 'A1','123',60,70,80 from dual
    union all
    select 'A2','124',30,100,90 from dual
    union all
    select 'A3','125',40,80,70 from dual
    /

错误：

  Error report:
    SQL Error: ORA-02291: integrity constraint (FAUZI.NIL_NIM_FK) violated - parent key not found
    02291. 00000 - "integrity constraint (%s.%s) violated - parent key not found"
    *Cause:    A foreign key value has no matching primary key value.
    *Action:   Delete the foreign key or add a matching primary key.