Intro to Database

A key that must be unique and cannot be null.

A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey.

A condition by which a dependent table's foreign key must have either a null entry or a matching entry in the related table.

• When an attribute is functionally dependent on a composite key but not on any subset of the key.
• AB ---> C, D, E

• 	\___/   /   /
  \______/   /

•  \________/

Create, Read, Update, Delete