What is key attribute and non key attribute?

A key attribute is a characteristic of an entity that uniquely identifies each instance of that entity in a database, such as a primary key in a table. For example, in a customer database, a customer ID serves as a key attribute. In contrast, a non-key attribute provides additional information about the entity but does not uniquely identify it; for instance, a customer's name or email address would be considered non-key attributes. Together, key and non-key attributes help structure and define the data within a database.