Jump to content

Unique identifier: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
General Cleanup; I use WP:LintHint, WP:AutoEd, Reference Organizer, spellcheck, then preview before publishing.
No edit summary
Tags: Reverted Mobile edit Mobile web edit
Line 2: Line 2:
{{Hatnote|Not to be confused with the [[UID (disambiguation)#Computing|many systems of unique identifiers]], many of which have non-unique proper names such as Unique Identifier, UID, or Unique Identification Number.}}
{{Hatnote|Not to be confused with the [[UID (disambiguation)#Computing|many systems of unique identifiers]], many of which have non-unique proper names such as Unique Identifier, UID, or Unique Identification Number.}}


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.<ref name="identifiers">{{Cite Q|Q33037209|author=McMurry, Julie A.|author2=Juty, Nick|author3=Blomberg, Niklas}}</ref> The concept was formalized early in the development of [[Computer science]] and [[Information system]]s. In general, it was associated with an [[Primitive data type|atomic data type]].
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.<ref name="identifiers">{{Cite Q||author=McMurry, Julie A.|author2=Juty, Nick|author3=Blomberg, Niklas}}</ref> The concept was formalized early in the development of [[Computer science]] and [[Information system]]s. In general, it was associated with an [[Primitive data type|atomic data type]].


In [[relational database]]s, certain attributes of an [[Entity-relationship model|entity]] that serve as unique identifiers are called [[primary key]]s.{{citation needed|date=July 2017}}<ref name="JurDfg">{{Cite book|title=SQL in a nutshell|last1=Kline|first1=Kevin E.|date=2009|publisher=O'Reilly|others=Kline, Daniel; Hunt, Brand|isbn=978-0-596-51884-4|edition=3rd|location=Beijing|oclc=244652620}}</ref>
In [[relational database]]s, certain attributes of an [[Entity-relationship model|E.2009|publisher=O'Reilly|others=Kline, Daniel; Hunt, Brand|isbn=978-0-596-51884-4|edition=3rd|location=Beijing|oclc=244652620}}</ref>


In Mathematics, the [[set theory]] uses the concept of ''[[Element (mathematics)|element]] [[Indexed family|indices]]'' as unique identifiers.
In Mathematics, the [[set theory]] uses the concept of ''[[Element (mathematics)|element]] [[Indexed family|indices]]'' as unique identifiers.

Revision as of 17:57, 10 September 2021

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.

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.[1] The concept was formalized early in the development of Computer science and Information systems. In general, it was associated with an atomic data type.

In relational databases, certain attributes of an [[Entity-relationship model|E.2009|publisher=O'Reilly|others=Kline, Daniel; Hunt, Brand|isbn=978-0-596-51884-4|edition=3rd|location=Beijing|oclc=244652620}}</ref>

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

Classification

There are some main types of unique identifiers,[1] each corresponding to a different generation strategy:

  1. serial numbers, assigned incrementally or sequentially, by a central authority or accepted reference.
  2. random numbers, selected from a number space much larger than the maximum (or expected) number of objects to be identified. Although not really unique, some identifiers of this type may be appropriate for identifying objects in many practical applications and are, with informal use of language, still referred to as "unique"
    1. Hash functions: based on the content of the identified object, ensuring that equivalent objects use the same UID.
    2. Random number generator: based on random process.
  3. names or codes allocated by choice which are forced to be unique by keeping a central registry such as the EPC Information Services.
  4. names or codes allocated using a regime involving multiple (concurrent) issuers of unique identifiers that are each assigned mutually exclusive partitions of a global address space such that the unique identifiers assigned by each issuer in each exclusive address space partition are guaranteed to be globally unique. Examples include (1) the media access control address MAC address uniquely assigned to each individual hardware network interface device produced by the manufacturer of the devices, (2) consumer product bar codes assigned to products using identifiers assigned by manufacturers that participate in GS1 identification standards, and (3) the unique and persistent Legal Entity Identifier assigned to a legal entity by one of the LEI registrars in the Global Legal Entity Identifier System (GLEIS) managed by the Global LEI Foundation (GLEIF).

The above methods can be combined, hierarchically or singly, to create other generation schemes which guarantee uniqueness.[2] In many cases, a single object may have more than one unique identifier, each of which identifies it for a different purpose.

Examples

National identification number

Main article: National identification number

National identification number is used by the governments of many countries as a means of tracking their citizens, permanent residents, and temporary residents for the purposes of work, taxation, government benefits, health care, and other governance-related functions.

Chemistry

Computing

Economics, tax and regulation

Internet architecture and standards

Mathematical publications

Science

Transportation

References

  1. ^ a b c
  2. ^ Cite error: The named reference JurDfg was invoked but never defined (see the help page).
  3. ^ Haak, Laurel L.; Fenner, Martin; Paglione, Laura; Pentz, Ed; Ratner, Howard (1 October 2012). "ORCID: a system to uniquely identify researchers". Learned Publishing. 25 (4): 259–264. doi:10.1087/20120404. ISSN 0953-1513. Wikidata Q30512726.
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Unique_identifier&oldid=1043555195"