Access-Control-Methods
August 25, 2024Software-Engineering
August 25, 2024ER-Model
Question 16
|
Consider the following relation schema
- Students(rollno: integer, sname: string)
Courses(courseno: integer, cname: string)
Registration(rollno: integer, courseno: integer, percent: real)
Which of the following queries are equivalent to this query in English?
"Find the distinct names of all students who score more than 90% in the course numbered 107"
(I) SELECT DISTINCT S.sname FROM Students as S,Registration as R WHERE R.rollno = S.roll AND R.courseno = 107 AND R.percent > 90 (II) Πsname(σcourseno=107∧percent>90(Registration ⋈ Students)) (III) {T|∃S ∈ Students, ∃R ∈ Registration (S.rollno = R.rollno ∧ R.courseno = 107 ∧ R.percent > 90 ∧ T.sname = S.sname)} (IV) {〈SN〉|∃SR∃RP(〈SR,SN〉 ∈ Students ∧ 〈SR,107,RP〉 ∈ Registration ∧ RP>90)}
I, II, III and IV
|
|
I, II and III only
|
|
I, II and IV only
|
|
II, III and IV only
|
Question 16 Explanation:
Four queries given in SQL, RA, TRC and DRC and all four statements will retrieve the required information.
Correct Answer: A
Question 16 Explanation:
Four queries given in SQL, RA, TRC and DRC and all four statements will retrieve the required information.
Subscribe
Login
0 Comments