Unique identifier

A unique identifier (UID) is an identifier that is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. The concept was formalized early in the development of computer science and information systems. In general, it was associated with an atomic data type.

Not to be confused with the many systems of unique identifiers, many of which have non-unique proper names such as Unique Identifier, UID, or Unique Identification Number.

In relational databases, certain attributes of an entity that serve as unique identifiers are called primary keys.

In mathematics, set theory uses the concept of element indices as unique identifiers.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.