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 constraints enforces entity integrity?

NOT NULL

FOREIGN KEY

CHECK

PRIMARY KEY

3 / 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

4 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

PRIMARY KEY

FOREIGN KEY

CHECK

5 / 50

The ER- data model is an example of:

Logical database

Physical database

Conceptual database

Relational database

6 / 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.·

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

by creating two separate tables

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

7 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

CHECK

FOREIGN KEY

PRIMARY KEY

8 / 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) -> ProjNo holds over R.

The functional dependency EmpNo -> DeptNo holds over R.

9 / 50

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

index

determinant

primary key

foreign key

10 / 50

Only B

A and B

B and C

Only A

11 / 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

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

by splitting each table into three

12 / 50

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

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

The domain of attribute must include only atomic values.

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

Every non-key attribute is partially dependent on super key

13 / 50

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

Database

DBMS

Data model

Data

14 / 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

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.

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

15 / 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.

16 / 50

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

1:01

Ternary

1:M

M:M

17 / 50

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

Transitive dependency

Any kind of dependency

Non-transitive dependency

Full functional dependency

18 / 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.

19 / 50

Identify the correct statement with respect to normalization.

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

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

20 / 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.

21 / 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.

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

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

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

22 / 50

Select the correct statement about the ANSI/SPARC architecture.

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.

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.

23 / 50

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.

24 / 50

Which of the following is true about relational schema?

Contains only derived attributes.

Values are atomic.

The sequence of rows is significant.

The sequence of columns is significant

25 / 50

A software package designed to store and manage databases

DBMS

Data

Database

Data model

26 / 50

A database system allows the following EXCEPT

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.

any user to access all its data.

integration of data across multiple applications into a single application

27 / 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.

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.

by splitting each table into three

28 / 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 row is unique.

Each column must have a unique name.

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

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

30 / 50

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

all sources/sinks (external entities)

one process (which represents the entire system)

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

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

31 / 50

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

all sources/sinks (external entities)

one process (which represents the entire system)

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

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

32 / 50

Which of the following is true for the relational model?

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

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.

33 / 50

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

DBMS

Data

Database

Data model

34 / 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.

35 / 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.

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.

Physical data independence.

Concurrency control.

37 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid inconsistency among data

avoid duplication

avoid unnecessary wastage of storage space

avoid unauthorised access to data

38 / 50

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

input and output

hardware

software

computer infrastructure

39 / 50

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

An identifying relationship

A recursive relationship

A binary relationship

A ternary relationship

40 / 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.

41 / 50

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

limit the values that can be placed in a column.

enforces that the column will only accept null values.

unique identifier for a row within a database table.

allow any actions that would destroy links between tables

42 / 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

43 / 50

The ER- data model is an example of:

Conceptual database

Physical database

Relational database

Logical database

44 / 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

45 / 50

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

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

all tuples in a relation must be distinct.

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.

46 / 50

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

End User

Application Programmer

Database Designer

Database Administrator

47 / 50

A collection of related data is

Database

Data

Logical model

Relational model

48 / 50

Which of the following is not a benefit of normalization?

Maximize redundancy

Minimize updation anomolies

Minimize deletion anomolies

Minimize insertion anomolies

49 / 50

Which of the following is true about NOT NULL constraint?

limit the values that can be placed in a column

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

enforce domain integrity

50 / 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.

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

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.

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