Here, we see the following attribute
* The student number is defined
as unique, such that no two customer rows may have the same
student_nbr. Oracle uses a unique index to enforce this primary
* The major name is validated
against the existing values in the MAJOR table when a row is
inserted. Hence, only valid department names are allowed to be
stored into the major_name column.
* The region_name column
may only have the values of N, S, E, or W. Oracle will not allow any
other values to be stored in this column.
Returning to our example from
Guttbaum’s Grocery, we remember that while the customer entity has
many attributes, each attribute is distinct and can be represented
independently of other attributes. The Oracle table definition for
Guttbaum's fact table might include the following customer