CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 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.

2 / 50

Which of the following is true about NOT NULL constraint?

enforces the uniqueness of the values in a set of columns

enforce domain integrity

limit the values that can be placed in a column

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

3 / 50

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

The domain of attribute must include only atomic values.

Every non-key attribute is partially dependent on super key

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

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

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)

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

all sources/sinks (external entities)

one process (which represents the entire system)

5 / 50

Select the correct statement among the following.

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

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

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

6 / 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

B and C

Only A

Only B

7 / 50

A collection of related data is

Relational model

Data

Database

Logical model

8 / 50

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

Database

Data

Data model

DBMS

9 / 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

10 / 50

Which of the following is true about relational schema?

The sequence of columns is significant

The sequence of rows is significant.

Values are atomic.

Contains only derived attributes.

11 / 50

statement among the following on the above diagram.

The diagram depicts existence dependencies.

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

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

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

12 / 50

User rights information is stored in

Logical database

Buffer

Physical database

Catalog

13 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

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.

14 / 50

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

ternary

binary

unary

weak

15 / 50

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

software

input and output

hardware

computer infrastructure

16 / 50

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

completeness

uniqueness

specialization

inheritance

17 / 50

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

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.

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

18 / 50

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

NOT NULL

UNIQUE

CHECK

FOREIGN KEY

19 / 50

Which of the following constraints enforces entity integrity?

CHECK

NOT NULL

FOREIGN KEY

PRIMARY KEY

20 / 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.

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

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

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

21 / 50

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.

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.

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

22 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

CHECK

FOREIGN KEY

NOT NULL

23 / 50

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

Full functional dependency

Non-transitive dependency

Transitive dependency

Any kind of dependency

24 / 50

Identify the correct statement.

Referential integrity constraints are specified between entities having recursive relationships.

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

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.

25 / 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

enforces that the column will only accept null values.

limit the values that can be placed in a column.

26 / 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 each table into three

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

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

27 / 50

Which of the following is true about relational schema?

Values are atomic.

The sequence of rows is significant.

Contains only derived attributes.

The sequence of columns is significant

28 / 50

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

one process (which represents the entire system)

all sources/sinks (external entities)

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

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

29 / 50

Which of the following is correct?

The relation Interview is in 3NF

The relation Interview is in BCNF.

The FD2 violates 2NF.

The FD3 violates 3NF.

30 / 50

A software package designed to store and manage databases

Data model

Database

DBMS

Data

31 / 50

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

DBMS

Data model

Database

Data

32 / 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.

33 / 50

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

Physical data independence.

Functional dependency

Concurrency control.

Logical data independence.

34 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unnecessary wastage of storage space

avoid unauthorised access to data

avoid inconsistency among data

avoid duplication

35 / 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.

36 / 50

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

determinant

foreign key

primary key

index

37 / 50

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

Authorization service

Recovery service

User accessible catalog

Data processing

38 / 50

Identify the INCORRECT statement among the given

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 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.

39 / 50

Which of the following is not a benefit of normalization?

Maximize redundancy

Minimize deletion anomolies

Minimize insertion anomolies

Minimize updation anomolies

40 / 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 specify that primary key values can be composite.

Entity integrity constraints are specified on individual relations.

Entity integrity constraints are specified between weak entities.

41 / 50

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

Planning, designing and implementing database systems

Establishing standards and procedures for database systems

Communicating with database users

Allocation of storage locations and data structures

42 / 50

Only B

Only A

A and B

B and C

43 / 50

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

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

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.

44 / 50

The ER- data model is an example of:

Conceptual database

Physical database

Logical database

Relational database

45 / 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.

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.

46 / 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 -> DeptNo holds over R.

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

47 / 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.

48 / 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.

49 / 50

A database system allows the following EXCEPT

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.

integration of data across multiple applications into a single application

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

any user to access all its data.

50 / 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 relation Interview is in 3NF

The FD2 violates 2NF.

The relation Interview is in BCNF.

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The average score is 22%