The image cncpt052.gif shows Table EMP, which has eight columns:

• EMPNO

• ENAME

• JOB

• MGR

• HIREDATE

• SAL

• COMM

• DEPTNO

The ENAME column has a NOT NULL Constraint--no row may contain a null value for this column. Column COMM has an absence of a NOT NULL Constraint--any row can contain null for this column.