What is the general database term for any set of one or more attributes whose…
2023
What is the general database term for any set of one or more attributes whose combined values uniquely identify a record, whether or not the set contains redundant attributes?
Answer: C. Superkey — ConceptUniqueness and minimality are separate properties of a relational key. Any set of attributes whose combined values uniquely identify every row is a…
- A.
Primary key
- B.
Foreign key
- C.
Superkey
- D.
More than one of the above
- E.
None of the above
Attempted by 2862 students.
Show answer & explanation
Correct answer: C
Concept
Uniqueness and minimality are separate properties of a relational key. Any set of attributes whose combined values uniquely identify every row is a superkey.
A candidate key is a minimal superkey: no attribute can be removed without losing uniqueness. One candidate key selected as the table’s main identifier is the primary key.
Application
The stem asks for the general term for any uniquely identifying attribute set and explicitly allows redundant attributes. That definition is superkey.
Contrast
Primary key names the selected minimal identifier, so it is a narrower role than the general category requested.
Foreign key names an attribute set used for referential integrity, not the general category of unique identifiers.
More than one of the above would require at least two listed terms to be equally broad names for every such set.
None of the above would require the general category to be absent from the list.
Cross-check
In Student(rollNo, email, name), suppose rollNo alone is unique. Then {rollNo, name} also uniquely identifies each row, but name is redundant. The pair is therefore a superkey while not being a candidate key or the primary key in that form.
Result
The general term is Superkey.