DBMS MCQ Questions and Answers

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Q331
Consider the relation
  • A The relation
  • B The functional dependency (VillageName, Lot#) (PropertyId, Area) violates 2NF.
  • C The relation
  • D The functional dependency Area VillageName violates 3NF.
Answer: Option A
Q332
Which of the following sets of operations represent a complete set of relational algebra operations?
  • A { σ, π, ∪}
  • B {
  • C { σ, π, ∩ }
  • D {π , ∩, σ, -}
Answer: Option A
Q333
Consider the sequence of operations given below on the relation Employee (EmpNo, Name, Address, Bdate, Gender, Salary, SuperNo, DNo). (i). DEP5_EMPS (σDNo=5 ( Employee)) (ii). RESULT1 πEmpNo(DEP5_EMPS) (iii). RESULT2(EmpNo) πSuperNo(DEP5_EMPS) (iv). RESULT RESULT1 RESULT2 What will the above sequence of operations performed on the given relation produce?
  • A EmpNo of the DNo 5 who work either as an employee or a supervisor.
  • B ) EmpNo of the employees who work in DNo 5 along with the employees of DNo 5 who work as supervisors.
  • C EmpNo of the DNo 5 employees who work as supervisors.
  • D EmpNo of the employees who either work in DNo 5 or supervise an employee who works in DNo 5.
Answer: Option D
Q334
If W, X, Y and Z are attributes of a relation, which of the following inference rules for functional dependencies is/are correct?
  • A If X Y then Y X.
  • B If X Y then (X, Z) (Y,W).
  • C If X (Y,Z) then X Y.
  • D If (X, Z) Y then X Y and Z Y.
Answer: Option C
Q335
Which of the following statements is/are correct, regarding a relation of the relational model? (a) Each relation in a database schema has a unique a name. (b) There can be multi-valued attributes in a relation. (c) Each row is identified uniquely. (d) The sequence of columns is significant.
  • A a and b
  • B a and c
  • C a,b and c
  • D All
Answer: Option B
Q336
Consider the following relations and the functional dependencies given thereafter. Project (Proj_Num, Proj_Name) Employee (Emp_Num, Emp_Name, Job_class, Chg_hours) Assign (Proj_Num, Emp_Num, Hours) FD1: Proj_Num, Emp_Num Hours FD2: Emp_Num Emp_Name, Job_class, Chg_Hours FD3: Proj_Num Proj_Name FD4: Job_class Chg_Hours Which of the following is/are correct in relation to the stated normal forms? (a) Project is in 1NF. (b) Employee is in 2NF. (c) Project is in 2NF. (d) Assign is in
  • A a and b
  • B a,b and c
  • C a,b,c and d
  • D a nd c
Answer: Option C
Q337
Which of the following statements is/are correct regarding normalization?
  • A It do not reduce update anomalies.
  • B It increases insertion anomalies.
  • C It minimizes redundancy.
  • D There in no zero normal form relations.
Answer: Option C
Q338
What are the reasons for a record structure to be de-normalised?
  • A When too many tables are generated due to normalization
  • B For efficiency purposes
  • C When too many joins are necessary to access frequently used data
  • D When Relational Algebra is inefficient in locating data
Answer: Option B
Q339
What are the anomalies which can be present due to un-normalised relations? (a) insertion (b) selection (c) deletion (d) update (e) none
  • A a and b
  • B a,b and c
  • C a,c and d
  • D a nd c
Answer: Option C
Q340
Consider the following statements about relational algebra. (i) Relational algebra is usually divided into two groups; one group includes set operations from mathematical set theory, and the other group consists of operations developed specifically for relational databases. (ii) The PROJECT operation is used to select a subset of tuples from a relation that satisfies a selection condition discarding some of the rows. (iii) Relational algebra is non-procedural. (iv) The DIVISION operation
  • A (i)
  • B (ii)
  • C (iii)
  • D (iv)
Answer: Option A

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