CQL for Cassandra 1.2

Using natural or surrogate primary keys

One consideration is whether to use surrogate or natural keys for a table. A surrogate key is a generated key (such as a UUID) that uniquely identifies a row, but has no relation to the actual data in the row.

For some tables, the data may contain values that are guaranteed to be unique and are not typically updated after a row is created. For example, the user name in a users table. This is called a natural key. Natural keys make the data more readable and remove the need for additional indexes or denormalization. However, unless your client application ensures uniqueness, it could potentially overwrite column data.