CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

A software package designed to store and manage databases

DBMS

Database

Data model

Data

2 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

Entity integrity constraints are specified on individual relations.

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

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

3 / 50

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

Functional dependency

Concurrency control.

Physical data independence.

Logical data independence.

4 / 50

Which of the following statements is NOT correct?

The functional dependency ProjNo -> DeptNo holds over R.

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

The functional dependency EmpNo -> DeptNo holds over R.

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

5 / 50

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

DBMS

Data

Database

Data model

6 / 50

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

Ternary

1:M

M:M

1:01

7 / 50

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

all tuples in a relation must be distinct.

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

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

all tuples in a particular relation may have different attributes.

8 / 50

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

End User

Database Designer

Application Programmer

Database Administrator

9 / 50

Which of the following is not a benefit of normalization?

Minimize updation anomolies

Minimize insertion anomolies

Maximize redundancy

Minimize deletion anomolies

10 / 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 the data into two tables with primary key and foreign key relationships

by splitting each table into three

11 / 50

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

Every non-key attribute is partially dependent on super key

The domain of attribute must include only atomic values.

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

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

12 / 50

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

completeness

specialization

inheritance

uniqueness

13 / 50

Identify the INCORRECT statement among the given

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.

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

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

14 / 50

Identify the correct way to implement one-to-one relationship in 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 creating two separate tables

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

15 / 50

Which of the following is true about relational schema?

The sequence of columns is significant

Values are atomic.

The sequence of rows is significant.

Contains only derived attributes.

16 / 50

Identify the correct statement.

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 are specified between weak entities.

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

Entity integrity constraints are specified on individual relations.

17 / 50

Structural constraints of a relationship type refer to

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.

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.

18 / 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 DeptNo -> ProjNo holds over R.

19 / 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 C.

Only A and B.

20 / 50

Identify the correct statement with respect to normalization.

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

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

Normalization can be used as a top-down standalone database design technique.

Normalization is a formal technique that can be used only at the starting phase of the database design.

21 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

FOREIGN KEY

CHECK

NOT NULL

22 / 50

Which of the following is true about relational schema?

The sequence of rows is significant.

Contains only derived attributes.

The sequence of columns is significant

Values are atomic.

23 / 50

Which of the following is correct?

The FD3 violates 3NF.

The relation Interview is in 3NF

The FD2 violates 2NF.

The relation Interview is in BCNF.

24 / 50

Which of the following is not true about relational tables?

The sequence of rows is significant.

Column values are of the same kind.

Each column must have a unique name.

Each row is unique.

25 / 50

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

by splitting each table into three

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

26 / 50

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

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

one process (which represents the entire system)

all sources/sinks (external entities)

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

27 / 50

Identify the correct statement.

Referential integrity constraints are specified between entities having recursive relationships.

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 the primary key values are unique.

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

28 / 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

Student ∩ Instructor

Instructor – Student

29 / 50

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

software

hardware

input and output

computer infrastructure

30 / 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 relation Interview is in BCNF.

The FD2 violates 2NF.

The FD3 violates 3NF.

The relation Interview is in 3NF

31 / 50

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

specialization

uniqueness

completeness

inheritance

32 / 50

A collection of related data is

Database

Data

Logical model

Relational model

33 / 50

Which of the following is true for the relational model?

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

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.

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

34 / 50

Select the correct statement about the ANSI/SPARC architecture.

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 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.

35 / 50

A database system allows the following EXCEPT

any user to access all its data.

integration of data across multiple applications into a single application

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.

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

36 / 50

statement among the following on the above diagram.

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

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

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

The diagram depicts existence dependencies.

37 / 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.

B and C

Only B

Only A

A and B

38 / 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

39 / 50

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

weak

unary

binary

ternary

40 / 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 ProjNo -> DeptNo holds over R.

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

41 / 50

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

Data

DBMS

Data model

Database

42 / 50

User rights information is stored in

Logical database

Physical database

Catalog

Buffer

43 / 50

User rights information is stored in

Catalog

Buffer

Physical database

Logical database

44 / 50

The ER- data model is an example of:

Conceptual database

Relational database

Logical database

Physical database

45 / 50

Which of the following is true about NOT NULL constraint?

limit the values that can be placed in a column

enforce domain integrity

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

enforces the uniqueness of the values in a set of columns

46 / 50

Structural constraints of a relationship type refer to

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

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

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

47 / 50

Select the correct statement among the following.

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

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.

48 / 50

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

NOT NULL

UNIQUE

FOREIGN KEY

CHECK

49 / 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

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

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.

50 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unnecessary wastage of storage space

avoid unauthorised access to data

avoid duplication

avoid inconsistency among data

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