You may have noticed two other checkboxes in the Edit Relationships dialog:

 

 

Cascade Update Related Fields ensures that when a primary key value is changed in the parent table, that value is also changed in the child table. Let’s say that you have Social Security numbers as your primary key field in the main table.

 

 

Let’s suppose that your company is changing to a system of employee ID numbers, and you now want that to be your primary key. You can change the primary key field to the Employee ID field, and the Social Security field will be replaced throughout the child tables.

 

 

Cascade Delete Related Records is a bit easier to understand. This option ensures that when a field in the primary table is deleted, related fields in the child table are deleted.