With data entry, it is often important to make sure that data is consistent. We are going to set up Referential Integrity.
Referential Integrity is a function which is used to make sure that data is consistent between related databases.
Go back to the relationships screen. Double click on the line between the two tables. This is the Edit Relationships menu. Click ok on Referential Integrity menu and click enforce referential integrity. An error message will be displayed if the data is inconsistent.