CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

A software package designed to store and manage databases

Data

DBMS

Database

Data model

2 / 50

Which of the following is true about relational schema?

Values are atomic.

Contains only derived attributes.

The sequence of rows is significant.

The sequence of columns is significant

3 / 50

As part of database naming conventions, attribute names should use suffixes such as ID, NUMBER or CODE for the _______.

determinant

foreign key

index

primary key

4 / 50

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

NOT NULL

FOREIGN KEY

CHECK

UNIQUE

5 / 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

6 / 50

Which of the following is not a benefit of normalization?

Minimize insertion anomolies

Maximize redundancy

Minimize updation anomolies

Minimize deletion anomolies

7 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

CHECK

PRIMARY KEY

FOREIGN KEY

8 / 50

Which of the following constraints enforces entity integrity?

CHECK

FOREIGN KEY

PRIMARY KEY

NOT NULL

9 / 50

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

Database Administrator

Database Designer

End User

Application Programmer

10 / 50

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

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

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.

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

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

11 / 50

Which of the following is true for the relational model?

Complex key is a key consisting of more than one attribute.

Constraint is a rule that restricts the values in a database.

Nullvalue is a blank or zero value given to an attribute value when its value is inapplicable or its value is unknown.

Degree of a relation is the number of rows in a relation.

12 / 50

Structural constraints of a relationship type refer to

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

identifying the owner entity type relevant to a given entity type

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.

13 / 50

The ER- data model is an example of:

Physical database

Logical database

Conceptual database

Relational database

14 / 50

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

Data

Database

DBMS

Data model

15 / 50

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

Data model

Database

DBMS

Data

16 / 50

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

allow any actions that would destroy links between tables

limit the values that can be placed in a column.

unique identifier for a row within a database table.

enforces that the column will only accept null values.

17 / 50

Which of the following is correct?

The relation Interview is in 3NF

The FD3 violates 3NF.

The FD2 violates 2NF.

The relation Interview is in BCNF.

18 / 50

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

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

all tuples in a particular relation may have different attributes.

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

all tuples in a relation must be distinct.

19 / 50

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

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

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

The domain of attribute must include only atomic values.

Every non-key attribute is partially dependent on super key

20 / 50

Which of the following is not true about relational tables?

Each row is unique.

Each column must have a unique name.

The sequence of rows is significant.

Column values are of the same kind.

21 / 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.

Only A

A and B

Only B

B and C

22 / 50

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

Student ∩ Instructor

Instructor ÷ Student

Instructor – Student

Student – Instructor

23 / 50

Which of the following statements is NOT correct?

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

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.

24 / 50

A collection of related data is

Data

Database

Logical model

Relational model

25 / 50

Only A

B and C

Only B

A and B

26 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid inconsistency among data

avoid unnecessary wastage of storage space

avoid unauthorised access to data

avoid duplication

27 / 50

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

Data processing

Recovery service

User accessible catalog

Authorization service

28 / 50

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

1:01

Ternary

M:M

1:M

29 / 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)

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

one process (which represents the entire system)

30 / 50

User rights information is stored in

Catalog

Physical database

Buffer

Logical database

31 / 50

The ER- data model is an example of:

Logical database

Relational database

Conceptual database

Physical database

32 / 50

Which of the following statements is NOT correct?

The functional dependency DeptNo -> ProjNo holds over R.

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.

33 / 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.

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.

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

34 / 50

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

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

by splitting each table into three

35 / 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.

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

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

36 / 50

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

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

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

by splitting each table into three

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

37 / 50

Which of the following functions are NOT performed by a database administrator?

Communicating with database users

Allocation of storage locations and data structures

Planning, designing and implementing database systems

Establishing standards and procedures for database systems

38 / 50

Which of the following is true about relational schema?

The sequence of rows is significant.

The sequence of columns is significant

Contains only derived attributes.

Values are atomic.

39 / 50

Which of the following statements is NOT correct?

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

The functional dependency ProjNo -> DeptNo holds over R.

The functional dependency EmpNo -> DeptNo holds over R.

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

40 / 50

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

completeness

inheritance

uniqueness

specialization

41 / 50

A database system allows the following EXCEPT

management and control of data towards an efficient working of an organisation.

integration of data across multiple applications into a single application

any user to access all its data.

more critical functions in organisations to be computerised and the need to keep a large volume of data available in an up to the minute current state increased.

42 / 50

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

A binary relationship

A recursive relationship

A ternary relationship

An identifying relationship

43 / 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.

Concurrency control.

Functional dependency

Physical data independence.

44 / 50

Select the correct statement among the following.

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.

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

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

45 / 50

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

one process (which represents the entire system)

all sources/sinks (external entities)

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

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

46 / 50

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

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.

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

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

47 / 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 FD3 violates 3NF.

The FD2 violates 2NF.

The relation Interview is in 3NF

The relation Interview is in BCNF.

48 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

NOT NULL

FOREIGN KEY

CHECK

49 / 50

User rights information is stored in

Catalog

Buffer

Logical database

Physical database

50 / 50

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

completeness

inheritance

uniqueness

specialization

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