DBMS MCQ Questions and Answers
DBMS MCQ questions with answers form a vital part of technical exams and campus interviews. This topic explores database concepts, normalization, SQL queries, transaction management, and ER models. Practicing programming questions and answers from this section strengthens your database design and query optimization skills. These questions are frequently asked in GATE, Infosys, TCS, and Wipro assessments, making them essential for students and professionals alike. Detailed solutions and explanations make this section perfect for both beginners and advanced learners aiming to master database management fundamentals.
DBMS MCQ
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527 questions
331. Consider the relation
- The relation
- The functional dependency (VillageName, Lot#) (PropertyId, Area) violates 2NF.
- The relation
- The functional dependency Area VillageName violates 3NF.
332. Which of the following sets of operations represent a complete set of relational algebra operations?
- { σ, π, ∪}
- {
- { σ, π, ∩ }
- {π , ∩, σ, -}
333. 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?
- EmpNo of the DNo 5 who work either as an employee or a supervisor.
- ) EmpNo of the employees who work in DNo 5 along with the employees of DNo 5 who work as supervisors.
- EmpNo of the DNo 5 employees who work as supervisors.
- EmpNo of the employees who either work in DNo 5 or supervise an employee who works in DNo 5.
334. If W, X, Y and Z are attributes of a relation, which of the following inference rules for functional dependencies is/are correct?
- If X Y then Y X.
- If X Y then (X, Z) (Y,W).
- If X (Y,Z) then X Y.
- If (X, Z) Y then X Y and Z Y.
335. 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 and b
- a and c
- a,b and c
- All
336. 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 and b
- a,b and c
- a,b,c and d
- a nd c
337. Which of the following statements is/are correct regarding normalization?
- It do not reduce update anomalies.
- It increases insertion anomalies.
- It minimizes redundancy.
- There in no zero normal form relations.
338. What are the reasons for a record structure to be de-normalised?
- When too many tables are generated due to normalization
- For efficiency purposes
- When too many joins are necessary to access frequently used data
- When Relational Algebra is inefficient in locating data
339. What are the anomalies which can be present due to un-normalised relations? (a) insertion (b) selection (c) deletion (d) update (e) none
- a and b
- a,b and c
- a,c and d
- a nd c
340. 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
- (i)
- (ii)
- (iii)
- (iv)