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  2. Superkey - Wikipedia

    en.wikipedia.org/wiki/Superkey

    A candidate key (or minimal superkey) is a superkey that can't be reduced to a simpler superkey by removing an attribute. [ 3 ] For example, in an employee schema with attributes employeeID , name , job , and departmentID , if employeeID values are unique then employeeID combined with any or all of the other attributes can uniquely identify ...

  3. Candidate key - Wikipedia

    en.wikipedia.org/wiki/Candidate_key

    A candidate key, or simply a key, of a relational database is any set of columns that have a unique combination of values in each row, with the additional constraint that removing any column could produce duplicate combinations of values. A candidate key is a minimal superkey, [1] i.e., a superkey that doesn't contain a smaller one. Therefore ...

  4. Boyce–Codd normal form - Wikipedia

    en.wikipedia.org/wiki/Boyce–Codd_normal_form

    However, only S 1, S 2, S 3 and S 4 are candidate keys (that is, minimal superkeys for that relation) because e.g. S 1 ⊂ S 5, so S 5 cannot be a candidate key. Given that 2NF prohibits partial functional dependencies of non-prime attributes (i.e., an attribute that does not occur in any candidate key ) and that 3NF prohibits transitive ...

  5. Super key - Wikipedia

    en.wikipedia.org/wiki/Super_key

    Super key may refer to: Super key (keyboard button), modifier key on keyboards; Superkey, database relation This page was last edited on 14 ...

  6. Third normal form - Wikipedia

    en.wikipedia.org/wiki/Third_normal_form

    Chris Date refers to Kent's summary as "an intuitively attractive characterization" of 3NF and notes that with slight adaptation it may serve as a definition of the slightly stronger Boyce–Codd normal form: "Each attribute must represent a fact about the key, the whole key, and nothing but the key." [9] The 3NF version of the definition is ...

  7. U.S. asked to extradite accused mastermind of ... - AOL

    www.aol.com/news/u-asked-extradite-accused...

    Mexico has asked the United States to extradite the suspected mastermind behind the murder of journalist Javier Valdez after he was arrested on drug charges, the attorney general said. Damaso ...

  8. Prisoners of Profit - The Huffington Post

    projects.huffingtonpost.com/prisoners-of-profit?...

    The private prison industry has long fueled its growth on the proposition that it is a boon to taxpayers, delivering better outcomes at lower costs than state facilities. But significant evidence undermines that argument: the tendency of young people to return to crime once they get out, for example, and

  9. List of SQL reserved words - Wikipedia

    en.wikipedia.org/wiki/List_of_SQL_reserved_words

    This list includes SQL reserved words – aka SQL reserved keywords, [1] [2] as the SQL:2023 specifies and some RDBMSs have added. Reserved words in SQL and related products In SQL:2023 [ 3 ]