Key Points

·          An attribute is a property of importance to the business whose values contribute to identifying, describing, or measuring instances of an entity.

·          A key is an attribute or set of attributes that helps us find entity instances.

·          A candidate key consists of one or more attributes that uniquely identify an entity instance. The candidate key that is selected as the best way to identify each unique record in the entity becomes the primary key. The other candidate keys become alternate keys. Keys containing more than one attribute are known as composite keys.

·          A surrogate key is a primary key with no embedded intelligence that is a substitute for a natural key. It is used by IT to facilitate integration and introduce database efficiencies.

·          A foreign key points from one entity instance to another.

·          A domain is a set of validation criteria that can be applied to more than one attribute.

·          There are three basic domain types: format, list, and range.