Question-15

Which of the following is NOT a super key in a relational schema with attributes V,

• VXYZ
• VWXZ
• VWXY
• VWXYZ

Answer

• VXYZ
• VWXZ
• VWXY
• VWXYZ

Solution

A super key is any super set of a candidate key (primary key). Given the primary key as “VY”: - \(VXYZ\) - Super key - \(VWXZ\) - Not a super key (as \(Y\) is not present) - \(VWXY\) - Super key - \(VWXYZ\) - Super key

Therefore, \(VWXZ\) is not a super key in this scenario.