Keys
Explore key attributes and their role in uniquely identifying entities within an entity set in an Entity-Relationship data model. Understand primary keys and how composite keys are formed by combining multiple attributes to ensure entity uniqueness.
We'll cover the following...
We'll cover the following...
Key attributes of an entity type
An important constraint on the entities of an entity type is the key or uniqueness constraint on attributes. An entity type usually has one or more attributes whose values are distinct for each individual entity in the entity set. Such an attribute is called a key attribute, and its values can be used to identify each entity uniquely. For the EMPLOYEE ...