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Key vs Superkey - What's the difference?

key | superkey |

As nouns the difference between key and superkey

is that key is an object designed to open and close a lock while superkey is any set of attributes of a relation variable (relvar) that serve to identify a single tuple or row, no other tuple having the same value for every attribute in the set.

As an adjective key

is indispensable, supremely important.

As a verb key

is to fit (a lock) with a key.

As a proper noun Key

is {{surname}.

key

English

Etymology 1

From (etyl) keye, kaye, . For the semantic development, note that medieval keys were simply long poles (ending in a hook) with which a crossbar obstructing a door from the inside could be removed from the outside, by lifting it through a hole in the door.

Noun

(en noun)
  • An object designed to open and close a lock.
  • * , chapter=13
  • , title= Mr. Pratt's Patients , passage=We tiptoed into the house, up the stairs and along the hall into the room where the Professor had been spending so much of his time. 'Twas locked, of course, but the Deacon man got a big bunch of keys out of his pocket and commenced to putter with the lock.}}
  • An object designed to fit between two other objects (such as a shaft and a wheel) in a mechanism and maintain their relative orientation.
  • A crucial step or requirement.
  • * (John Locke) (1632-1705)
  • Those who are accustomed to reason have got the true key of books.
  • * (1809-1892)
  • who keeps the keys of all the creeds
  • A guide explaining the symbols or terminology of a map or chart; a legend.
  • A guide to the correct answers of a worksheet or test.
  • (label) One of several small, usually square buttons on a typewriter or computer keyboard, mostly corresponding to text characters.
  • (label) One of a number of rectangular moving parts on a piano or musical keyboard, each causing a particular sound or note to be produced.
  • (label) One of various levers on a musical instrument used to select notes, such as a lever opening a hole on a woodwind.
  • (label) A hierarchical scale of musical notes on which a composition is based.
  • * 1881 , R.L. Stevenson, :
  • A girl, it is true, has always lived in a glass house among reproving relatives, whose word was law; she has been bred up to sacrifice her judgments and take the key submissively from dear papa; and it is wonderful how swiftly she can change her tune into the husband's.
  • (label) The general pitch or tone of a sentence or utterance.
  • * (William Cowper) (1731-1800)
  • You fall at once into a lower key .
  • (label) An indehiscent, one-seeded fruit furnished with a wing, such as the fruit of the ash and maple; a samara.
  • (label) A manual electrical switching device primarily used for the transmission of Morse code.
  • (label) A piece of information (e.g. a passphrase) used to encode or decode a message or messages.
  • (label) A password restricting access to an IRC channel.
  • * 2000 , "Robert Erdec", Re: Help; mIRC32; unable to resolve server arnes.si'' (on newsgroup ''alt.irc.mirc )
  • if you know someone who is in the channel, you can query them and ask for the key .
  • (label) In a relational database, a field used as an index into another table (not necessarily unique).
  • (label) A value that uniquely identifies an entry in an associative array.
  • (label) The free-throw lane together with the circle surrounding the free-throw line, the free-throw lane having formerly been narrower, giving the area the shape of a skeleton key hole.
  • (label) A series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon.
  • (label) Kilogram (though this is more commonly shortened to kay ).
  • * 2010 , David J. Silas, Da Block (page 41)
  • So starting with ten keys' of cocaine and two ' keys of heroin, Derrick put his plan in motion. Soon every major drug dealer and gang chief from Chicago Avenue to Evanston was in his pocket.
  • (label) A piece of wood used as a wedge.
  • (label) The last board of a floor when laid down.
  • (label) A keystone.
  • That part of the plastering which is forced through between the laths and holds the rest in place.
  • (rail transport) A wooden support for a rail on the bullhead rail system.
  • (label) The object used to open or close a lock, often used as a heraldic charge.
  • Derived terms
    (Derived terms) * candidate key * card key * church key * foreign key * keyboard * keycard * key card * keychain, key chain * key fob, keyfob * keyhole * keynote * keypad * keyring, key ring * key signature * keystone * keystroke * keyword * major key * minor key * Morse key * primary key * public-key cryptography * skeleton key * unique key
    See also
    * clef * scale * (wikipedia "key") *

    Adjective

    (en adjective)
  • Indispensable, supremely important.
  • He is the key player on his soccer team.
  • * 2007 , Mark H. Moss, Shopping as an Entertainment Experience (page 46)
  • Lukas intimates that one of Disney's key attractions was "Main Street USA,” which "mimicked a downtown business district just as Southdale" had done.
  • Important, salient.
  • She makes several key points.
  • * {{quote-book, year=2006, author=
  • , title=Internal Combustion , chapter=2 citation , passage=Throughout the 1500s, the populace roiled over a constellation of grievances of which the forest emerged as a key focal point. The popular late Middle Ages fictional character Robin Hood, dressed in green to symbolize the forest, dodged fines for forest offenses and stole from the rich to give to the poor. But his appeal was painfully real and embodied the struggle over wood.}}
  • * {{quote-news
  • , year=2011 , date=September 29 , author=Jon Smith , title=Tottenham 3 - 1 Shamrock Rovers , work=BBC Sport citation , page= , passage=With the north London derby to come at the weekend, Spurs boss Harry Redknapp opted to rest many of his key players, although he brought back Aaron Lennon after a month out through injury.}}
    Usage notes
    The first meaning is distinguished by the definite article, as seen in the quotations.

    Verb

    (en verb)
  • To fit (a lock) with a key.
  • To fit (pieces of a mechanical assembly) with a key to maintain the orientation between them.
  • To mark or indicate with a symbol indicating membership in a class.
  • * 1996 January, Garden Dsign Ideas , second printing, (Taunton Press), ISBN 1561580791, page 25,
  • So I worked on a tissue-paper copy of the perimeter plan, outlining groupings of plants of the same species and keying them with letters for the species.
  • * 2001 , Bruce M. Metzger, The Bible in Translation , ISBN 0801022827, page 87,
  • The volume closes with thirty pages of "Notes, critical and explanatory," in which Thomson provides seventy-six longer or shorter notes keyed to specific sections of the synopsis.
  • * 2002 , Karen Bromley, Stretching Students' Vocabulary , ISBN 0439288398, page 12,
  • Talk about similarities between the words and write them below to the left of the anchor, keying' them with a plus sign (+). Talk about the characteristics that set the words apart and list them below the box to the right, ' keying them with a tilde sign (~).
  • * 2007 , Stephen Blake Mettee, Michelle Doland and Doris Hall, compilers, The American Directory of Writer's Guidelines , 6th ("2007–2008") edition, ISBN 1884956580, page 757,
  • Indicate the comparative value of each heading by keying it with a number in pencil, in the left margin, as follows:
  • (telegraphy and radio telegraphy) To depress (a telegraph key).
  • (radio) To operate (the transmitter switch of a two-way radio).
  • (computing) (more usually to key in ) To enter (information) by typing on a keyboard or keypad.
  • Our instructor told us to key in our user IDs.
  • (colloquial) To vandalize (a car, etc.) by scratching with an implement such as a key.
  • He keyed the car that had taken his parking spot.
  • To link (as one might do with a key or legend).
  • * 1960 , Richard L. Masland, "Classification of the Epilepsies", in Epilepsia , volume 1, page 516,
  • The American Heart Association has prepared their own guide to classification and, keying it with the Standard Nomenclature of Diseases , have done much to encourage a concise yet complete diagnosis.
  • * '>citation
  • * '>citation
  • (intransitive, biology, chiefly, taxonomy) To be identified as a certain taxon when using a key.
  • To fasten or secure firmly; to fasten or tighten with keys or wedges.
  • (Francis)
    Derived terms
    * key in * key off * key out * keyed up

    Etymology 2

    Variant of cay, from (etyl) cayo.

    Alternative forms

    * cay

    Noun

    (en noun)
  • One of a string of small islands.
  • "the Florida Keys "

    Anagrams

    *

    Etymology 3

    superkey

    English

    Noun

    (en noun) (wikipedia superkey)
  • (databases) Any set of attributes of a relation variable (relvar) that serve to identify a single tuple or row, no other tuple having the same value for every attribute in the set.