When one is concerned about an object identification so as to make objects recoverable via their identity, a system of
UniqueIdentifiers is usually devised. Whether a collectable signed and numbered by the originator, or a file name in a filing system, or an object or method in an
ObjectOriented system, or a pattern. Those who are concerned about
OnceAndOnlyOnce will necessarily be found utilizing methods of identification which are unique.
Other more numerous reasons for
UniqueIdentifiers can be found in:
Universal Identifiers
Use
GloballyUniqueIdentifiers (GUIDs) in Access and SQL Server
When does a Unique Identifier not need to be used?
ItDepends on Context:
Also, there's the 'tag' URI protocol, which I first saw proposed to be used within
AtomSyntax for handling unique ids:
Related:
Contrast with
GroupsAreNotUnique
CategoryOrganization