What is meant by natural key?

What is natural key with example?

Natural key. A key that is formed of attributes that already exist in the real world. For example, U.S. citizens are issued a Social Security Number (SSN) that is unique to them (this isn't guaranteed to be true, but it's pretty darn close in practice).

What is a natural key vs primary key?

A primary key uniquely identifies each record within a table and relates records to additional data stored in other tables. A natural key might require several fields to accomplish a unique identity for each record.

What is a natural key in data warehousing?

In data warehouse tables, natural keys are meaningful values that identify records, such as social security numbers that identify specific customers, calendar dates in a time dimension, or SKU numbers in a product dimension. In some cases, natural keys are unique identifiers and can serve as primary keys.

How do you define a natural key in SQL?

A natural key is a column or set of columns that already exist in the table (e.g. they are attributes of the entity within the data model) and uniquely identify a record in the table. Since these columns are attributes of the entity they obviously have business meaning.