CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

A collection of related data is

Database

Relational model

Data

Logical model

2 / 50

Which of the following is correct?

The FD3 violates 3NF.

The relation Interview is in BCNF.

The FD2 violates 2NF.

The relation Interview is in 3NF

3 / 50

Identify the INCORRECT statement among the given

Age can be considered as a single value attribute of a person.

An entity may be an object with a physical existence like a car, a house or an Employee.

An entity type describes the schema or intension for a set of entities which share the same structure.

One cannot consider something which has conceptual existence like a course in a degree program as an entity.

4 / 50

Which of the following is NOT a feature of Context DFD?

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

one process (which represents the entire system)

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

all sources/sinks (external entities)

5 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

Entity integrity constraints specify that primary key values can be composite.

Entity integrity constraints are specified on individual relations.

When entity integrity rules are enforced, a tuple in one relation that refers to another relation must refer to an existing tuple.

6 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unauthorised access to data

avoid unnecessary wastage of storage space

avoid inconsistency among data

avoid duplication

7 / 50

Which of the following statements is NOT correct?

The functional dependency (EmpNo, ProjNo) -> DeptNo holds over R

The functional dependency EmpNo -> DeptNo holds over R.

The functional dependency DeptNo -> ProjNo holds over R.

The functional dependency ProjNo -> DeptNo holds over R.

8 / 50

A ____ relationship exists when an association is maintained within a single entity.

weak

ternary

unary

binary

9 / 50

The ER- data model is an example of:

Conceptual database

Physical database

Logical database

Relational database

10 / 50

Identify the correct statement.

When Referential integrity rules are enforced, a tuple in one relation that refers to another relation must refer to an existing tuple.

Referential integrity constraints check whether an attribute value lies in the given range.

Referential integrity constraints are specified between entities having recursive relationships.

Referential integrity constraints check whether the primary key values are unique.

11 / 50

Which of the following is true about NOT NULL constraint?

enforce domain integrity

enforces the uniqueness of the values in a set of columns

prevents any actions that would destroy links between tables with the corresponding data values

limit the values that can be placed in a column

12 / 50

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 FD2 violates 2NF.

The relation Interview is in 3NF

The relation Interview is in BCNF.

The FD3 violates 3NF.

13 / 50

Which of the following is NOT a feature of Context DFD?

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

all sources/sinks (external entities)

one process (which represents the entire system)

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

14 / 50

A collection of concepts that can be used to describe the structure of a database

Database

Data model

DBMS

Data

15 / 50

Which of the following is not true about relational tables?

Each row is unique.

Column values are of the same kind.

Each column must have a unique name.

The sequence of rows is significant.

16 / 50

Which of the following is INCORRECT statement concerning the database design process?

During the logical design phase of internal storage structures, access paths and file organization for the database files are specified

By referring to a high level data model, it is possible to understand the data requirements of the users, entity types, relationships and constraints

During requirements collection and analysis phase, one can gather the data requirements of database users.

Transformation of the high level data model into the implementation data model is called logical design or data model mapping

17 / 50

Consider the following statements.
A. Conceptual schema which is the result of conceptual design is a logical description of all data elements and their relationships.
B. Internal level of the database architecture consists of the physical view of the database.
C. External level of the database architecture provides the user view of the database.
With respect to the ANSI/SPARC three level database architecture, which of the above is/are correct?

Only B and C.

Only A.

Only A and B.

Only C.

18 / 50

statement among the following on the above diagram.

The relationship type Y is of cardinality ratio 1 : N.

The participation of X in the Y relationship type is total.

The diagram depicts existence dependencies.

The participation of Z in the Y relationship type is partial.

19 / 50

Which of the following is INCORRECT with respect to file systems?

The efficiency of a file system depends on how efficiently operations such as retrieve, insert, update, delete may be performed on the information stored in the file.

At the physical level, pointer or hashed address scheme may be employed to provide a certain degree of data independence at the user level.

A logical record is concerned with efficient storage of information in the secondary storage devices.

Some physical organisations use pointers to record blocks to locate records on disk.

20 / 50

The ____ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.

uniqueness

specialization

inheritance

completeness

21 / 50

Which feature of database provides conversion from inconsistent state of DB to a consistent state ensuring
minimum data loss?

Recovery service

User accessible catalog

Data processing

Authorization service

22 / 50

Which of the following is a feature of PRIMARY KEY constraint?

unique identifier for a row within a database table.

allow any actions that would destroy links between tables

limit the values that can be placed in a column.

enforces that the column will only accept null values.

23 / 50

Which of the following most certainly implies the need for an entire table to implement?

A recursive relationship

A binary relationship

An identifying relationship

A ternary relationship

24 / 50

Select the correct statement about the ANSI/SPARC architecture.

The external level is not concerned with individual user perceptions, while the conceptual level is concerned with a community user perception.

The conceptual level is a level of indication between the internal level and the external level.

Any given database has many conceptual schemas and one physical schema, but it has only one external schemas.

The internal level in a database system will definitely be relational.

25 / 50

Identify the correct way to implement one-to-one relationship in tables?

as a single table and rarely as two tables with primary and foreign key relationships.

by creating two separate tables

by splitting the data into two tables with primary key and foreign key relationships.·

using a junction table with the keys from both the tables forming the composite primary key of the junction table.

26 / 50

Which of the following constraints enforces entity integrity?

FOREIGN KEY

PRIMARY KEY

CHECK

NOT NULL

27 / 50

User rights information is stored in

Physical database

Buffer

Catalog

Logical database

28 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

FOREIGN KEY

CHECK

PRIMARY KEY

29 / 50

Which of the following is not a benefit of normalization?

Minimize deletion anomolies

Maximize redundancy

Minimize insertion anomolies

Minimize updation anomolies

30 / 50

Who is responsible for authorizing access to the database, for coordinating and monitoring its use?

Database Administrator

Database Designer

Application Programmer

End User

31 / 50

User rights information is stored in

Buffer

Logical database

Catalog

Physical database

32 / 50

Database management systems, operating systems, applications and utilities are all examples of ____.

software

input and output

hardware

computer infrastructure

33 / 50

Making a change to the conceptual schema of a database but not affecting the existing external schemas is an example of

Logical data independence.

Physical data independence.

Concurrency control.

Functional dependency

34 / 50

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

Student ∩ Instructor

Instructor – Student

35 / 50

Structural constraints of a relationship type refer to

the constraints applicable in granting access to tables, columns and views in a database schema.

whether the existence of an entity depends on it being related to another entity via the relationship type.

identifying the owner entity type relevant to a given entity type

the role that a participating entity from the entity type plays in each relationship instance.

36 / 50

A collection of concepts that can be used to describe the structure of a database

Data model

Database

Data

DBMS

37 / 50

The ____ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.

inheritance

completeness

specialization

uniqueness

38 / 50

Which of the following enforces a relation into 1st normal form?

non-key attribute is non-transitively dependent on primary key.

The domain of attribute must include only atomic values.

Every non-key attribute is partially dependent on super key

Every non-key attribute is fully functionally dependent on primary key

39 / 50

Consider the following statements.
A. An entity integrity constraint states that no primary key value can be null.
B. A referential integrity constraint is specified between two relations.
C. A foreign key cannot be used to refer to its own relation.
Identify which of the above statements is/are correct.

A and B

Only B

Only A

B and C

40 / 50

Which of the following is a correct way to implement one-to-many relationship while designing tables?

using a junction table with the keys from both the tables forming the composite primary key of the junction table.

by splitting the data into two tables with primary key and foreign key relationships

by splitting each table into three

as a single table and rarely as two tables with primary and foreign key relationships

41 / 50

A and B

Only A

B and C

Only B

42 / 50

In a conceptual model for a university, what type of relationship exists between Grade and Student entities?

Ternary

1:01

1:M

M:M

43 / 50

Which of the following is true about relational schema?

Contains only derived attributes.

The sequence of columns is significant

The sequence of rows is significant.

Values are atomic.

44 / 50

Identify the correct statement.

Entity integrity constraints are specified on individual relations.

When entity integrity rules are enforced, a tuple in one relation that refers to another relation must refer to an existing tuple.

Entity integrity constraints specify that primary key values can be composite.

Entity integrity constraints are specified between weak entities.

45 / 50

A software package designed to store and manage databases

DBMS

Data model

Data

Database

46 / 50

Identify the constraint that limits the values that can be placed in a column.

CHECK

NOT NULL

FOREIGN KEY

UNIQUE

47 / 50

Which of the following statements is NOT correct?

The functional dependency EmpNo -> DeptNo holds over R.

The functional dependency (EmpNo, ProjNo) -> DeptNo holds over R.

The functional dependency ProjNo -> DeptNo holds over R.

The functional dependency (EmpNo, DeptNo) -> ProjNo holds over R.

48 / 50

A relation (from the relational database model) consists of a set of tuples, which implies that

all tuples in a particular relation may have different attributes.

for any two tuples, the values associated with all ofheirt attributes may be the same.

all tuples in a relation must be distinct.

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

49 / 50

The ER- data model is an example of:

Physical database

Relational database

Conceptual database

Logical database

50 / 50

Select the correct statement among the following.

Role names are not technically necessary in relationship types when all the participating entity types are distinct.

Cardinality ratios for binary relationship are displayed on Entity Relationship Diagrams by using a diamond shape notation

Partial participation which is also called existence dependency is displayed as a double line connecting the participating entity type to the relationship.

When different entity types participate only once in a single relationship type it is called a recursive relationship

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