A candidate key for a relation is a set of its attributes that satisfy:
• Uniqueness. The values of the attributes uniquely identify a
tuple.
• Minimality. No proper subset of the attributes has the uniqueness
property.
If uniqueness is satisfied (but not necessarily minimality) the attributes
are said to form a superkey.
• Uniqueness. The values of the attributes uniquely identify a
tuple.
• Minimality. No proper subset of the attributes has the uniqueness
property.
If uniqueness is satisfied (but not necessarily minimality) the attributes
are said to form a superkey.
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