Question:
Consider a database that includes the following relations :
Defender(name, rating, side, goals)
Forward(name, rating, assists, goals)
Team(name, club, price)
Which ONE of the following relational algebra expressions checks that every name occurring in Team appears in either Defender or Forward, where Φ denotes the empty set ?
Consider a database that includes the following relations :
Defender(name, rating, side, goals)
Forward(name, rating, assists, goals)
Team(name, club, price)
Which ONE of the following relational algebra expressions checks that every name occurring in Team appears in either Defender or Forward, where Φ denotes the empty set ?
Defender(name, rating, side, goals)
Forward(name, rating, assists, goals)
Team(name, club, price)
Which ONE of the following relational algebra expressions checks that every name occurring in Team appears in either Defender or Forward, where Φ denotes the empty set ?
Updated On: Feb 3, 2026
- Пname (Team) \ (Пname (Defender) ∩ Пname (Forward)) = Φ
- (Пname (Defender) ∩ (Пname (Forward) \ Пname (Team) = Φ
- Пname (Team) \ (Пname (Defender) ∪ Пname (Forward)) = Φ
- (Пname (Defender) ∪ (Пname (Forward) \ Пname (Team)) = Φ
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The Correct Option is C
Solution and Explanation
The correct option is (C) : Пname (Team) \ (Пname (Defender) ∪ Пname (Forward)) = Φ.
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