Unique identifier With reference to a given set of objects, a unique is any identifier which is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. The concept have been formalized early in identifier Computer science and Information systems, in general associating it to an atomic data type. 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 as unique identifiers. element indices ClassificationThere are some main types of unique identifiers, each corresponding to a different generation strategy: The above methods can be combined, hierarchically or singly, to create other generation schemes which guarantee uniqueness. In many cases, a single object may have more than one unique identifier, each of which identifies it for a different purpose. serial numbers, assigned incrementally or sequentially, by a central authority or accepted reference. random numbers, selected from a number space much larger than the maximum 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" # Hash functions: based on the content of the identified object, ensuring that equivalent objects use the same UID. # : based on Random number generator random process. names or codes allocated by choice which are forced to be unique by keeping a central such as the registry EPC Information Services. names or codes allocated using a regime involving multiple 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 the media access control address MAC address uniquely assigned to each individual hardware network interface device produced by the manufacturer of the devices, consumer product bar codes assigned to products using identifiers assigned by manufacturers that participate in GS1 identification standards, and 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 managed by the Global LEI Foundation. ExamplesNational 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
Popular articles Angela Merkel - German politician who has been Chancellor of Germany since 2005. She served as the Leader of the Christian Democratic Union from 2000 to 2018. Merkel has been widely desc... Oleksandr Usyk - Ukrainian professional boxer. He reigned as the undisputed cruiserweight champion from 2018 until he vacated his titles in 2019, being the first cruiserweight in h... Next German federal election - The next German federal election for the 20th Bundestag is expected to be held between August and October 2021. Background. Previous election. The 2017 federal elections were held after a four-ye... Social Democratic Party of Germany - social-democratic political party in Germany. It is one of the two major contemporary political parties in Germany along with the Christian Democratic Uni... Cleopatra - Cleopatra VII Philopator was the last active ruler of the Ptolemaic Kingdom of Egypt. As a member of the Ptolemaic dynasty, she was a descendant of its founder Ptolemy I Soter, a Macedonian Greek ge... Sex Education (TV series) - British comedy-drama web television series created by Laurie Nunn. Starring Asa Butterfield as an insecure teenager and Gillian Anderson as his mother, a sex therapist, the series... YouTube - American online video-sharing platform headquartered in San Bruno, California. Three former PayPal employees—Chad Hurley, Steve Chen, and Jawed Karim—created the service in Februar... Popular movies Dune (2020 film) - upcoming 2020 epic science fiction film directed by Denis Villeneuve with a screenplay by Jon Spaihts, Eric Roth and Villeneuve. The film... Free Guy - upcoming American science fiction action comedy film directed by Shawn Levy from a screenplay by Matt Lieberman and Zak Penn and a story by Lieberman. The film stars Ryan Reynolds, Jo... No Time to Die - forthcoming spy film and the twenty-fifth instalment in the James Bond film series produced by Eon Productions. The film features Daniel Craig in his fifth and final outing as ... Shang-Chi and the Legend of the Ten Rings - upcoming American superhero film based on the Marvel Comics character Shang-Chi. Produced by Marvel Studios and distributed by Walt Disney Studios Mot... Venom: Let There Be Carnage - upcoming American superhero film based on the Marvel Comics character Venom, produced by Columbia Pictures in association with Marvel. Distributed by Sony Pictures ... Dune (1984 film) - 1984 American epic science fiction film written and directed by David Lynch and based on the 1965 Frank Herbert novel of the same name. The film stars Kyle MacLachlan as young nobleman Pau... Black Widow (2020 film) - upcoming American superhero film based on the Marvel Comics character of the same name. Produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures, it is int... Popular video games Roblox - online game platform and game creation system that allows users to program games and play games created by other users. Founded by David Baszucki and Erik Cassel in 2004 and released in... Genshin Impact - upcoming open-world action role-playing video game developed by miHoYo. It is the second game from miHoYo to feature original IP, the first being Gun GirlZ . History. Genshin... League of Legends - multiplayer online battle arena video game developed and published by Riot Games for Microsoft Windows and macOS. Inspired by Defense of the Ancients , the game follows a fre... Diablo II - action role-playing hack-and-slash computer video game developed by Blizzard North and published by Blizzard Entertainment in 2000 for Microsoft Windows, Classic Mac OS, and macOS. T... Grand Theft Auto V - 2013 action-adventure game developed by Rockstar North and published by Rockstar Games. It is the first main entry in the Grand Theft Auto series since 2008's Grand Theft ... Kena: Bridge of Spirits - upcoming action-adventure game developed and published by Ember Lab. It is scheduled for release in late 2020 for Microsoft Windows, PlayStation 4, and PlayStation 5. G... Deltarune - role-playing video game created by Toby Fox. The player controls a human, Kris, in a world inhabited by monsters. Kris and a classmate named Susie fall into an unknown place called th... Popular books Dune (novel) - 1965 science fiction novel by American author Frank Herbert, originally published as two separate serials in Analog magazine. It tied with Roger Zelazny's This Immortal for the Hugo Aw... Foundation (Asimov novel) - science fiction novel by American writer Isaac Asimov. It is the first published in his Foundation Trilogy . Foundation ... Bible - collection of religious texts or scriptures sacred to Christians, Jews, Samaritans, Rastafari and others. They generally consider the Bible to be a product of divine inspiration and a... Nineteen Eighty-Four - dystopian novel by English novelist George Orwell. It was published on 8 June 1949 by Secker & Warburg as Orwell's ninth and final book... SCP Foundation - fictional organization documented by the web-based collaborative-fiction project of the same name. Within the website's fictional setting, the SCP Foundation is responsible f... James Bond - The James Bond series focuses on a fictional British Secret Service agent created in 1953 by writer Ian Fleming, who featured him in twelve novels and two short-story collections. Since Fleming's de... The Witcher - fantasy series of novels and short stories written by Polish author Andrzej Sapkowski. The series revolves around the titular "witcher", Geralt of Rivia. In Sapkowski's wo... Popular television series
Sex Education (TV series) - British comedy-drama web television series created by Laurie Nunn. Starring Asa Butterfield as an insecure teenager and Gillian Anderson as his mother, a sex therapist, the series... Foundation (TV series) - upcoming American science fiction television series based on the book series of the same name by Isaac Asimov and produced for Apple TV+. The series was in pre-production, but on Ma... Money Heist - Spanish heist crime drama television series created by Álex Pina. The series traces two long-prepared heists led by the Professor, one on the Royal Mint of Spain, and one on the Ba... What If...? (TV series) - upcoming American animated web television anthology series created for Disney+ by A.C. Bradley, based on the Marvel Comics series of the same name. It explores what would happen if... The Walking Dead (TV series) - American post-apocalyptic horror television series for AMC based on the comic book series by Robert Kirkman, Tony Moore, and Charlie Adlard. The series features a large ensemb... Ted Lasso (TV series) - continuation of the character Sudeikis portrayed in a series of promos for NBC... The Sandman (TV series) (television series) - The Sandman (TV series) - Netflix's future television adaptation of Neil Gaiman's "The Sandman."....
OWIKI.org. Text is available under the Creative Commons Attribution-ShareAlike License.