DATABASE QUIZ 1

1.In Linear Hashing, we never see overflow buckets.  

Select one:
True
False {correct}

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

http://en.wikipedia.org/wiki/Database_storage_structures

3.A relation (table) can have any number of unique keys (attribute/s) .  

Select one:
True {correct}
False

http://en.wikipedia.org/wiki/Unique_key

4.The notation 1:N/ M:N/ 1:1 used in ER diagrams are to represent___ of a relationship.
Select one:
a. Cardinality {correct}
b. Degree
c. Multiplicity
d. Arity

5.The entity type  which doesn't have a key is called as a _____
Select one:
a.  Secondary entity type
b. Dependent entity type
c. Weak entity type {correct}
d. Partial entity type

6.Relational Algebra is more expressive than Relational Calculus.

Select one:
True
False {correct}

http://www.felixgers.de/teaching/sql/db_relational_algebra.html

7.Any FD  of the form  X-->Y;  must satisfy which of the following, to be in BCNF?
Select one:
a. X must be a Super Key {correct}
b. Y must be a key attribtes
c. X and Y must be keys
d. X and Y must be key attributes

8.In relational algebra, if we have two relations R(A,B,C) and S(B), then the result relation T which is the result of R÷S will have following attributes. 
Select one:
A
C
A,C {correct}
A,B

9.If we have a FD  X --> Y, then  WX --> Y is also a valid FD.                  

Select one:
True {correct}
False

10.In ER modeling, a strong (Regular) entity type can have maximum of ______ number of keys (unique).

Select one:
a. Two
b. One
c. Zero or more
d. One or more {correct}

11.The number of cylinders in a Disk-pack is same as number of sectors on a track.   

Select one:
True
False {correct}

12.The three schema architecture of the DBMS leads to___

Select one:
Database Recovery
Data Abstraction
Data Integrity
Data Independence {correct}

13.Relational Calculus is a declarative query language for Relational model.     

Select one:
True {correct}
False

14.The Natural join is performed on Relations with__

Select one:
a. With same Keys
b. Same number of columns and types
c. Common attributes (similar labels) {correct}
d. Same number of tuples

15.If an Extendible Hashing scheme starts with Global Depth=3 and Local Depth=1, we have ___ buckets (blocks) allotted to the file in the beginning.
Select one:
a. 4
b. 0
c. 2 {correct}
d. 8

16.The result of a relational algebraic expression is ___ 
Select one:
a. Another Relational Expression
b. Any of the above
c. A relation {correct}
d. An Object

17.In spanned record organization, some space may be wasted at the end of each block. 
Select one:
True
False {correct}


18.A candidate key is a____
Select one:
a.Foreign key
b.Primary key    
c.Minimal super key  {correct}
d.Alternate key        

19.The matrix approach used for determining if a decomposition is lossless, can be used for binary decomposition also.  

Select one:
True {correct}
False

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

21.Assume a Data file with 10 blocks, and if each block can take 4 records, and total 24 records are stored in the file, the value of File Load Factor (f)  at that moment is-

Select one:
a. 10/6
b. 4/24
c. 40/24
d. 24/40 {correct}

22.In a relation ordering of tuples is  not significant.   

Select one:
True {correct}
False

23.A data model is a collection of___

Select one:
Set of concepts used to describe the DB {correct}
Tables
Records
Entities

24.ER modeling is a ____
Select one:
a. High level data model {correct}
b. NW data model
c. External data model
d. Low level data model

25.All 3NF to BCNF decompositions are always dependency preserving. 

Select one:
True
False {correct}