Computer Science

1. 1.

   For Student(StudentID, Name) with StudentID declared PRIMARY KEY and Enrolment(StudentID, CourseID) with StudentID declared NOT NULL, explain the primary key and a foreign-key constraint referencing Student.

   [3 marks] · no calculator
2. 2.

   Explain an update anomaly when DepartmentName is repeated in every employee row, and suggest a relational remedy.

   [3 marks] · no calculator
3. 3.

   Given Scores(Name, Mark), write SQL to return names with Mark >= 70 sorted by descending Mark then ascending Name. Do not require duplicate removal.

   [3 marks] · no calculator
4. 4.

   Orders contains (OrderID, CustomerID): (1,A), (2,A), (3,B). Customer contains IDs A, B and C once each. Determine row counts for an inner join on CustomerID and a customer-left join with Orders.

   [3 marks] · no calculator
5. 5.

   A relation Enrolment(StudentID, CourseID, StudentName, CourseTitle, Grade) has key (StudentID, CourseID); StudentName depends only on StudentID and CourseTitle only on CourseID. Decompose it to remove the partial dependencies and explain how Grade is retained.

   [4 marks] · no calculator
6. 6.

   A bank transfer debits one account then credits another. Explain how atomicity and isolation address different risks if a crash or concurrent balance update occurs.

   [4 marks] · no calculator

Original, unofficial practice questions from SubjectScout — not official past-paper questions.