Which key of a relation is always a minimal keys?

1.	Which key of a relation is always a minimal keys?
Answer» Candidate key is a set of attributes (or attribute) which uniquely identify the tuples in a relation or\xa0table. As we know that\xa0Primary key\xa0is a minimal\xa0super key, so there is one and only one\xa0primary key\xa0in any relation but there is more than one candidate key can take place.\xa0A superkey is a set of attributes within a table whose values can be used to uniquely identify a tuple. A candidate\xa0key\xa0is a\xa0minimal\xa0set of attributes necessary to identify a tuple; this is also called a\xa0minimal\xa0superkey

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