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INTRO. TO DATABASE MGMT. SYST.
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Consider a relation R(A, B, C, D) with the functional dependencies:
- A → B
- B → C
- C → D
What is the highest normal form satisfied by R?
Given the following SQL query:
studinfo(studid, name, sex)enroll(studId, courseId)
SELECT DISTINCT e.courseIdFROM enroll eWHERE e.courseId NOT IN ( SELECT e1.courseId FROM enroll e1 JOIN studInfo s ON e1.studId = s.studId WHERE s.sex = 'male');
Which of the following Relational Algebra expressions correctly represents this query?
Consider a relation R(P, Q, R, S, T, U) with the following functional dependencies: 1. P → QR 2. Q → S 3. R → TU
Which of the following functional dependencies must also hold?
Given the following SQL query:
studinfo(studid, name, sex)enroll(studId, courseId)
SELECT DISTINCT e.courseIdFROM enroll eWHERE e.courseId NOT IN ( SELECT DISTINCT e1.courseId FROM enroll e1 JOIN studInfo s ON e1.studId = s.studId WHERE s.sex = 'female');
Which of the following Relational Algebra expressions correctly represents this query?
Given the following SQL query:
SELECT student_id FROM Enrollments WHERE course = 'Math' INTERSECT SELECT student_id FROM Enrollments WHERE course = 'Science';
Which of the following Relational Algebra expressions correctly represents this query?
A relation is in 3NF if:
Consider a relation R(A, B, C, D, E) with functional dependencies: 1. A → B 2. B → C 3. CD → E
R is decomposed into R1(A, B, C) and R2(C, D, E).
Is this decomposition dependency preserving?
Consider a relation R(M, N, O, P, Q, R) with the following functional dependencies: 1. MN → OP 2. O → Q 3. P → R
R is decomposed into R1(M, N, O, P) and R2(O, Q, P, R).
Is this decomposition lossless?
Given the following SQL query:
SELECT student_id FROM Enrollments EXCEPT SELECT student_id FROM Exams;
Which of the following Relational Algebra expressions correctly represents this query?
Which of the following relations is in BCNF?