As previously noted, primary keys are used to relate tables to each other within Access. When a primary key field is placed in a related table for the sole purpose of creating a relationship, that field is then referred to as a Foreign Key. In the image below, the Pets table is shown as having three foreign keys: OwnerID, VetID and AnimID. OwnerID allows for the record of an individual Pet to be related to its owner’s records. VetID allows for the record of an individual Pet to be related to the appropriate veterinarian data. AnimID allows for the record of an individual Pet to be related to its animal type.

Note that there is no key symbol denoting a foreign key. It is the use of the primary key from one table as the relating field in another table and the establishment of the relationship between the tables that creates the foreign key. Conceptually, this can be difficult to understand. Foreign keys will be explored more in the next unit and video tutorials will walk through how to set them up for the Menagerie Kennel database.