A ____ is an attribute or combination of attributes that uniquely identifies a tuple.
A)secondary key
B)primary key
C)foreign key
D)preferred key

Question

Quizplus · Accepted Answer

A primary key is an attribute or a combination of attributes that uniquely identifies a tuple in a relation. It ensures that no two rows have the same value in the primary key column(s) and that a primary key value cannot be NULL.

A ____ Is an Attribute or Combination of Attributes That