CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 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.

2 / 50

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

inheritance

uniqueness

specialization

completeness

3 / 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

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

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.

4 / 50

Which of the following constraints enforces entity integrity?

CHECK

NOT NULL

PRIMARY KEY

FOREIGN KEY

5 / 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.

all tuples in a relation must be distinct.

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

6 / 50

Which of the following is not a benefit of normalization?

Minimize deletion anomolies

Maximize redundancy

Minimize updation anomolies

Minimize insertion anomolies

7 / 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)

8 / 50

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

NOT NULL

UNIQUE

CHECK

FOREIGN KEY

9 / 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)

10 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid inconsistency among data

avoid duplication

avoid unauthorised access to data

avoid unnecessary wastage of storage space

11 / 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 are specified between weak entities.

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

12 / 50

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

Data model

Data

DBMS

Database

13 / 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 diagram depicts existence dependencies.

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

14 / 50

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

Authorization service

Recovery service

Data processing

User accessible catalog

15 / 50

Which of the following concepts is applicable with respect to 2NF?

Transitive dependency

Non-transitive dependency

Full functional dependency

Any kind of dependency

16 / 50

Identify the INCORRECT statement among the given

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

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.

17 / 50

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

Application Programmer

Database Designer

Database Administrator

End User

18 / 50

Which of the following is true about NOT NULL constraint?

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

limit the values that can be placed in a column

enforces the uniqueness of the values in a set of columns

enforce domain integrity

19 / 50

A software package designed to store and manage databases

DBMS

Data

Data model

Database

20 / 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.

21 / 50

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

Data

Database

Data model

DBMS

22 / 50

The ER- data model is an example of:

Physical database

Logical database

Conceptual database

Relational database

23 / 50

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

specialization

uniqueness

completeness

inheritance

24 / 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

25 / 50

Which of the following statements is NOT correct?

The functional dependency ProjNo -> DeptNo holds over R.

The functional dependency DeptNo -> ProjNo holds over R.

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

The functional dependency EmpNo -> DeptNo holds over R.

26 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

FOREIGN KEY

CHECK

NOT NULL

27 / 50

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

foreign key

index

primary key

determinant

28 / 50

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

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.

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.

29 / 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

30 / 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

A and B

Only A

Only B

31 / 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 3NF

The relation Interview is in BCNF.

The FD3 violates 3NF.

The FD2 violates 2NF.

32 / 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.

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

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

33 / 50

A collection of related data is

Logical model

Relational model

Database

Data

34 / 50

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

Allocation of storage locations and data structures

Planning, designing and implementing database systems

Establishing standards and procedures for database systems

Communicating with database users

35 / 50

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

Instructor – Student

Instructor ÷ Student

Student – Instructor

Student ∩ Instructor

36 / 50

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

Functional dependency

Logical data independence.

Concurrency control.

Physical data independence.

37 / 50

Which of the following is not true about relational tables?

Each column must have a unique name.

The sequence of rows is significant.

Column values are of the same kind.

Each row is unique.

38 / 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.

39 / 50

Which of the following is correct?

The FD2 violates 2NF.

The relation Interview is in 3NF

The FD3 violates 3NF.

The relation Interview is in BCNF.

40 / 50

User rights information is stored in

Buffer

Physical database

Logical database

Catalog

41 / 50

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

1:01

M:M

Ternary

1:M

42 / 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 fully functionally dependent on primary key

Every non-key attribute is partially dependent on super key

43 / 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 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.

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

44 / 50

Identify the correct statement.

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.

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

45 / 50

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.

46 / 50

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

A ternary relationship

A recursive relationship

A binary relationship

An identifying relationship

47 / 50

The ER- data model is an example of:

Conceptual database

Relational database

Physical database

Logical database

48 / 50

Which of the following statements is NOT correct?

The functional dependency ProjNo -> DeptNo holds over R.

The functional dependency EmpNo -> DeptNo holds over R.

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

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

49 / 50

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

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

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

50 / 50

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

weak

binary

unary

ternary

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The average score is 22%