When you create a Microsoft Access table, Access will automatically create a primary key to your database table. Still, you can also specify the field you want as the primary key for your database ...

Cascading referential integrity constraints are foreign key constraints that tell SQL Server to perform certain actions when a primary key field in a primary key-foreign key relationship is updated or ...

I'm adding a table and subclass table to my DB. (Subclass table = table where the primary key joins to the primary key of another table, to give extra row information to some subset of the rows.