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Thursday, November 29, 2012

MIDTERM EXAMINATION CS403 past old paper




MIDTERM EXAMINATION CS403- Database Management Systems
Question No: 1    ( Marks: 1 )    - Please choose one
User rights information is stored in
Physical database

Catalog

Logical database

Buffer



Question No: 2    ( Marks: 1 )    - Please choose one
Making a change to the conceptual schema of a database but not affecting the existing external schemas is an example of

Physical data independence.
Concurrency control.

Logical data independence.
Functional dependency

Question No: 3    ( Marks: 1 )    - Please choose one
Which of the following is NOT a feature of Context DFD?


data flows linking the process to the sources and sinks (external entities)

sub-processes (which explain and decomposed the major process into small processes)



Question No: 4    ( Marks: 1 )    - Please choose one
A relation (from the relational database model) consists of a set of tuples, which implies that
       º all tuples in a relation must be distinct.


       º relational model supports multi-valued attributes whose values can be represented in sets.


       º for any two tuples, the values associated with all of their attributes may be the same.


       º all tuples in a particular relation may have different attributes.



Question No: 5    ( Marks: 1 )    - Please choose one
Choose the symbol that corresponds to a discriminator attributes.














Question No: 6    ( Marks: 1 )    - Please choose one
Identify the constraint that limits the values that can be placed in a column.

NOT NULL

CHECK                               No Idea

FOREIGN KEY

UNIQUE



Question No: 7    ( Marks: 1 )    - Please choose one
Given are the relations of student and Instructor
















Consider the following table obtained using Student and Instructor relations.



Which relational algebra operation could have been applied on the pair of relations Student and
Instructor to obtain the above data?

Instructor Student
Student Instructor
Instructor ÷ Student
Student Instructor



Question No: 8    ( Marks: 1 )    - Please choose one
Identify the correct statement with respect to normalization.


Normalization is a formal technique that can be used only at the starting phase of the database design.
Normalization can be used as a top-down standalone database design technique.
The process of normalization through decomposition must achieve the lossless join property at any cost whereas the dependency reservation property is sometimes
sacrificed.

The process of normalization through decomposition must achieve the dependency reservation property at any cost whereas the lossless join property is sometimes
sacrificed.



Question No: 9    ( Marks: 1 )    - Please choose one
Consider the relation Interview(CandidateNo, InterviewDate, InterviewTime, StaffNo, RoomNo)
and the following functional dependencies.
FD1 : CandidateNo, InterviewDate -> InterviewTime, StaffNo, RoomNo
FD2 : RoomNo, InterviewDate, InterviewTime -> StaffNo, CandidateNo
FD3 : StaffNo, InterviewDate -> RoomNo
Which of the following is correct?

The relation Interview is in 3NF
The relation Interview is in BCNF.
The FD3 violates 3NF.
The FD2 violates 2NF.

Question No: 10    ( Marks: 1 )    - Please choose one
Identify the INCORRECT statement among the given.
An entity may be an object with a physical existence like a car, a house or an Employee.
One cannot consider something which has conceptual existence like a course in a degree


program as an entity.

Age can be considered as a single value attribute of a person.
An entity type describes the schema or intension for a set of entities which share the same structure.



Question No: 11    ( Marks: 1 )    - Please choose one
Structural constraints of a relationship type refer to

identifying the owner entity type relevant to a given entity type
whether the existence of an entity depends on it being related to another entity via the relationship type.

the role that a participating entity from the entity type plays in each relationship instance.
the constraints applicable in granting access to tables, columns and views in a database schema.



Question No: 12    ( Marks: 1 )    - Please choose one
A collection of concepts that can be used to describe the structure of a database

Database

DBMS
Data model
Data

Question No: 13    ( Marks: 1 )    - Please choose one
hyperlink
common attribute
primary key
superkey

Question No: 14    ( Marks: 1 )    - Please choose one

The

constraint specifies whether each entity supertype occurrence must also be a

member of at least one subtype.
specialization
uniqueness
inheritance
completeness

Question No: 15    ( Marks: 1 )    - Please choose one
Database management systems, operating systems, applications and utilities are all
examples of         .
hardware


software
computer infrastructure
input and output

Question No: 16    ( Marks: 1 )    - Please choose one
Which of the following concepts is applicable with respect to 2NF?
Full functional dependency
Any kind of dependency
Transitive dependency
Non-transitive dependency



Question No: 17    ( Marks: 2 )
What do you know about Insertion anomaly?
Insertion anomaly indicates that we cannot insert a fact about one entity until we have an additional fact about another entity.



Question No: 18    ( Marks: 2 )
Define domain of an attribute.
In computing, the attribute domain is the set of values allowed in an attribute. For the relational model it is a requirement that each part of a tuple be atomic. The consequence is that each value in the tuple must be of some basic type, like a string or an integer. For the elementary type to be atomic it cannot be broken into more pieces.






1...
2...

Label the following diagram


Question No: 20     ( Marks: 3 )
Why do the relational data model considered as simple?
The relational model for database management is a database model based on first-order predicate logic The relational modeprovide a declarative method for specifying data and queries: we directly state what information the database contains and what information we want from it, and let the database management system software take care of describing data
structures for storing the data and retrieval procedures for getting queries answered

Question No: 21     ( Marks: 3 )
What is the intersection operation in relational algebra?


The intersection operation also has the requirement that both the relations should be union compatible, which means they are of same degree and same domains. It is represented by. If R and S are two relations and we take intersection of these two
relations then the resulting relation would be the set of tuples, which are in both R and
S. Just like union intersection is also commutative.
R _ S = S _ R INTERSECTION Example





Question No: 22     ( Marks: 5 )
The following diagram describes a part of an ER diagram.

Considering the above diagram, which of the given statements are True and which are
False.

i-Entity2 is a weak entity. True


ii-Cardinality ratio for Entity1:Entity2 in Rel1 is 1:N. True
iii-Attrib6 represents an attribute which is having composite nature. False
iv-Attrib3 is a kind of a derived attributes. True
v-Entity2 is participating totally in the Rel1 relationship.



Question No: 23     ( Marks: 5 )
How to implement one-to-many relationship while designing tables?

If the primary key in a parent table matches multiple foreign keys in a child table, then the relationship is one-to-many. This relationship is common in database applications. For example, an application for a sports league might access a team table and a
player table. Each team has multiple players, and each player belongs to a single
team. Every row in the child table (player) has a foreign key identifying the player's team. This foreign key matches the team table's primary key.

When designing such entity beans, you must decide whether both tables are represented by entity beans, or just one.

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