Database Reference
In-Depth Information
Figure 10.63. Designating the degree of participation for the primary and foreign
keys of the STAFF table
Youcandesignatean
unlimited
degreeofparticipationforanytableinadual-tablerelation-
ship or key field in a self-referencing relationship by using an “N” in place of the second
number. For example, the ORDERS table in
Figure 10.64
has an unlimited degree of parti-
cipation.Althoughanewcustomermayhavenotyetplacedanorder,youwillallowhimto
place as many orders as he wishes. Imagine the impact on your organization's business if
you limited each customer to 35 orders! Your organization would soon be out of business,
unless it could continually and consistently acquire new customers.
Figure 10.64. Designating an unlimited degree of participation for the ORDERS
table
Your task now is to set the relationship characteristics for every relationship you've estab-
lished thus far. As you complete work on a given relationship, be sure to update the rela-
tionship diagram so that it reflects the results of your work.
Verifying Table Relationships with Users and Management
The very last order of business is to verify the relationships. You can perform this task rel-
atively easily by using the following checklist.
1.
Make sure that you've properly identified each relationship.
