Modifying Referential Integrity
For purposes of illustration we are going to modify our
business rules a bit. Let us say that a worker may clock
time against a work order number even though the work order
has not been entered yet. The foreman can enter the order
later.
Enforcing referential integrity would prevent this from
occurring. We would not be able to enter a labor ticket that
did not refer to an existing work order record. So, we need
to modify the relationship between the labor table and the
work_orders table to allow this.
Right click on the relationship line between labor and
work_orders.
Select edit relationships to bring up the edit relationship
dialogue. Clear the enforce referential integrity checkbox.
Close the dialogue box. You will then see that Microsoft
Access has removed the symbols at the end of the
relationship lines. This means that referential integrity is
not being enforced.
I would NOT normally do this in a production database. I
created this example to illustrate how the designer changes
the relationships window diagram. Whenever you see a
relationship line with no end symbols you know that
referential integrity is not being enforced. This is true in
the query design window as well.
Continue to page 4 - modifying join properties...
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