Database Reference
In-Depth Information
sures consistency among the values of both fields in both tables and helps to estab-
lish relationship-level integrity.
Figure 10.55. Logical Elements for the E
MPLOYEE
ID N
UMBER
primary key field in
the EMPLOYEES table
Review the foreign keys in each table to make certain that they conform to the Elements
of a Foreign Key, and make the appropriate modifications to those that fail to do so. You
reallyshouldn'tencounteranyproblemsifyou'vebeenfaithfullyfollowingthedesignpro-
cess up to this point.
Establishing Relationship Characteristics
Now you'll establish the characteristics of each relationship. These characteristics indicate
what will occur when you delete a record, the type of participation each table bears within
the relationship, and to what degree each table participates in the relationship.
