DEPTNO (Primary Key of referenced table) | DNAME | LOC |
---|---|---|
20 | RESEARCH | DALLAS |
30 | SALES | NEW YORK |
40 | MARKETING | BOSTON |
EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO (Foreign Key; values in dependent table must match a value in unique key or primary key of referenced table) |
---|---|---|---|---|---|---|---|
7329 | SMITH | CEO | N/A | 17-DEC-85 | 9,000.00 | N/A | 20 |
7499 | ALLEN | VP-SALES | 7329 | 20-FEB-90 | 7,500.00 | 100.00 | 30 |
7521 | WARD | MANAGER | 7499 | 22-FEB-90 | 5,000.00 | 200.00 | 30 |
7586 | JONES | SALESMAN | 7521 | 02-APR-90 | 2,975.00 | 400.00 | 20 |
EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO | Comments |
---|---|---|---|---|---|---|---|---|
7571 | FORD | MANAGER | 7499 | 23-FEB-90 | 5,000.00 | 200.00 | 50 | This row violates the referential constraint because "50" is not present in the referenced table's primary key; therefore, the row is now allowed in the table. |
7571 | FORD | MANAGER | 7499 | 23-FEB-90 | 5,000.00 | 200.00 | N/A | This row is allowed in the table because a null value is entered in the DEPTNO column; however, if a not null constraint is also defined for this column, this row is not allowed. |