Database Design and Applications (S2-14_SSZG518)

1.Assume that we have two tables EMP and DEPT. Now when we execute the SQL query- "SELECT * FROM EMP, DEPT; "  ,and which is syntactically perfect, which of the following is correct- 

Select one:
a.Result will have EMP tuples joined with DEPT table  if some join condition is met.
b.It is Cartesian product of EMP and DEPT
c.Gives zero tuples in the result.
d.Shows SQL error since no join condition in WHERE clause

Answer: b

2.Assume that a relation R(A, B, C, D) with F={A>BCD; C>D}, is decomposed in to R1(A,B,D) and R2(A,C). Then the projection of F on R1 includes the  A > C.      
Select one:
True
False

Answer: False

3.Relational Data model is a strictly structured data model.  
Select one:
True
False

Answer: True

4.In Extendible hashing scheme, if we start with GD=3, and LD=2, then how many buckets are allocated for storing data records, in the beginning?
Select one:
a.1
b.8
c.4
d.2

Answer: c

5.For the relation R(A,B,C,D), with F={AB>C, AB>D, D>B}, the highest NF satisfied is____.
Select one:
a.BCNF
b.1NF
c.2NF
d.3NF

Answer: d

6.In case of unordered files, inserting a new record into the file is very easy compared to ordered files.
Select one:
True
False

Answer: True

7.In the process of testing whether a given decomposition is lossy or not, we need not compute the closure of original set of FDs (F) of the original undecomposed relation.
Select one:
True
False

Answer: True

8.Assume that a relation R(A, B, C, D) with F={A>BCD; C>D}, is decomposed in to R1(A,B,D) and R2(A,C). Then this decomposition is Dependency preserving.          
Select one:
True
False

Answer: False

9.Which of the following query languages is not declarative?
Select one:
a.Tuple Relational Calculus
b.DRC
c.Relational Algebra
d.SQL

Answer: c

10. In Linear Hashing scheme a random bucket can get its split image when the split criterion is met.
Select one:
True
False

Answer: False

11.If we have a FD  X (p) Y, and Y>Z, then  WX (p) Z is also a valid FD.
Select one:
True
False

Answer:False

12. We have foreign keys in  ER modeling.              
Select one:
True
False

Answer: False

13. The ordering of tuples in a relation is not significant.
Select one:
True
False

Answer: True

14. Relational Algebra is more expressive than SQL.        
Select one:
True
False

Answer: True

15. In ER modeling, the relationship between a weak entity type and its corresponding owner entity type is known as  ______ Relationship.
Select one:
a.Partial
b.Depending
c.Weak
d.Identifying

Answer: d

16.If the R/W head of a Disk-pack is on the appropriate track from where we need to read data, then the time required to place the R/W head at the beginning of the required sector/block is known as-

Select one:
a.Sector latency
b.Rotation delay
c.Sector delay
d.Disk latency

Answer:b

17.In relational algebra, the result of projection operation includes duplicates.
Select one:
True
False

Answer: False

18.In a relation, a primary key attribute can also be a foreign key.
Select one:
True
False

Answer:True

19.Why Functional Dependencies are so significant?

Select one:
a.Because they reflect data types for attributes
b.Because they represent Foreign keys
c.Because they are essential for data security
d.Because they represent business logic or some constraint.

Answer: d

20.In a disk-pack with uniform disk/surface configuration, the number of cylinders in the Disk-pack is same as number of tracks on a surface.
Select one:
True
False

Answer: True

21. In Normalization process, all decompositions that are lossless are also dependency preserving.
Select one:
True
False

Answer: False

22.The database design step, where we translate the high-level conceptual schema to implementation specific conceptual schema (Ex.  ER to Relational Schema) is known as _______ step.
Select one:
a.Implementation DB design
b.Logical DB design
c.Conceptual DB design
d.Schema refinement

Answer: b

23.For any functional dependency of the form X --> Y, in a relation, BCNF requires that      
Select one:
a.X must be a key
b.Y must be akey
c.X and Y both must be key attributes
d.Y must be a key attribute 

Answer: a

24.A data model is a collection of tables and relationships.
Select one:
True
False

Answer: False

25.In spanned record organization, some records are stored across two disk blocks.  That is some portion is one block and remainder is in the next.
Select one:
True
False

Answer: True