Find the ID, name, dept name, salary for instructors whose salary is greater than $80,000 .
A. {t | t ε instructor ∧ t[salary] > 80000}
B. Э t ∈ r (Q(t))
C. {t | Э s ε instructor (t[ID] = s[ID]∧ s[salary] > 80000)}
D. Only a and b
Answer:A
Find the ID, name, dept name, salary for instructors whose salary is greater than $80,000 .
A. {t | t ε instructor ∧ t[salary] > 80000} B. Э t ∈ r (Q(t)) C. {t | Э s ε instructor (t[ID] = s[ID]∧ s[salary] > 80000)} D. Only a and b
Explanation:This expression is in tuple relational format. 2. A query in the tuple relational calculus is expressed as: