Database Reference
In-Depth Information
Figure 10.56. What deletion rule is appropriate for a given relationship?
Select a relationship, look at the diagram, and pose the following question:
When a record in the (
name of parent table
) table is deleted,
what should happen to related records in the (
name of child table
)
table?
Herethequestionisframedinagenericmannersothatyoucanunderstandthepremisebe-
hind it. When you pose this question for a pair of tables in a particular relationship, substi-
tute the phrases within the parentheses with the appropriate table names. If you're working
with the relationship between the EMPLOYEES and ORDERS table, you could pose the
question in this manner:
