What are the different types of keys used in the database?

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Hi!!

Can someone list the various types of leys used in the database?
Nov 19, 2018 in Database by DataKing99
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There are mainly 5 types of Keys, that can be mentioned in the database.

  • Candidate Key – The minimal set of attributes which can uniquely identify a tuple is known as a candidate key. A relation can hold more than a single candidate key, where the key is either a simple or composite key.
  • Super Key – The set of attributes which can uniquely identify a tuple is known as Super Key. So, a candidate key is a superkey, but vice-versa isn’t true.
  • Primary Key – A set of attributes that can be used to uniquely identify every tuple is also a primary key. So, if there are 3-4 candidate keys present in a relationship, then out those, one can be chosen as a primary key.
  • Alternate Key – The candidate key other than the primary key is called as an alternate key.
  • Foreign Key – An attribute that can only take the values present as the values of some other attribute, is the foreign key to the attribute to which it refers.
answered Nov 19, 2018 by darklord
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