ORA-02291: integrity constraint (STARTUP.SUPER_SSN_FK) violated - parent key not foun

[AKERMAN1]

CREATE TABLE EMPLOYEE
( Fname VARCHAR2(25) NOT NULL,
Lname VARCHAR2(25) NOT NULL,
Ssn CHAR(9) CONSTRAINT SSN_PK PRIMARY KEY,
DOB DATE,
Address VARCHAR2(30),
Sex CHAR,
Salary DECIMAL(10,2),
Super_ssn CHAR(9),
DEPT_ID  NUMBER 
 );

Table created.

ALTER TABLE EMPLOYEE
ADD CONSTRAINT DEPT_ID_FK FOREIGN KEY (DEPT_ID) REFERENCES DEPARTMENT (DEPT_ID) 
ADD CONSTRAINT SUPER_SSN_FK FOREIGN KEY (Super_ssn) REFERENCES EMPLOYEE (SSN) ;


CREATE TABLE DEPARTMENT
( DEPT_NAME VARCHAR2(25) UNIQUE NOT NULL,
DEPT_ID NUMBER CONSTRAINT DEPT_ID_PK PRIMARY KEY,
MGR_SSN CHAR(9) NOT NULL,
Mgr_start_date DATE);

Table created.

ALTER TABLE DEPARTMENT
ADD CONSTRAINT DEPT_MGR_FK FOREIGN KEY (MGR_SSN) REFERENCES EMPLOYEE(SSN);

SQL> insert into department
  2  values('sales',0002,'24-march-1988','123456789');
insert into department
*
ERROR at line 1:
ORA-02291: integrity constraint (STARTUP.DEPT_MGR_FK) violated - parent key not
found
SQL> INSERT INTO EMPLOYEE
  2  VALUES('JOHN','SMITH',123456784,'20-JUNE-1976','24,MONGROMERY','M', 4000,123456789,1);
INSERT INTO EMPLOYEE
*
ORA-02291: integrity constraint (STARTUP.SUPER_SSN_FK) violated - parent key not found

[Rabbit]

I'm not sure what your question is. The error is pretty clear, you're violating the foreign keys you set up. When you set up a foreign key, the foreign key must exist when you insert that record. The foreign key records don't exist, that's why you're getting the error.