CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

Identify the correct statement.

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.

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

Referential integrity constraints are specified between entities having recursive relationships.

2 / 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.

3 / 50

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

Data

Database

DBMS

Data model

4 / 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.

5 / 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.

6 / 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)

7 / 50

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

inheritance

completeness

uniqueness

specialization

8 / 50

The ER- data model is an example of:

Logical database

Physical database

Relational database

Conceptual database

9 / 50

Structural constraints of a relationship type refer to

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.

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

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

10 / 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

Only A

Only B

B and C

11 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

PRIMARY KEY

FOREIGN KEY

CHECK

12 / 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 internal level in a database system will definitely be relational.

Any given database has many conceptual schemas and one physical schema, but it has only one external schemas.

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

13 / 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

14 / 50

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

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

limit the values that can be placed in a column.

15 / 50

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

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.

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

16 / 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.

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

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.

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

17 / 50

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

by splitting each table into three

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

18 / 50

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

FOREIGN KEY

CHECK

UNIQUE

NOT NULL

19 / 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.

20 / 50

Which of the following statements is NOT correct?

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

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.

21 / 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.

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.

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

22 / 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.

23 / 50

User rights information is stored in

Buffer

Physical database

Logical database

Catalog

24 / 50

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

Database Designer

End User

Database Administrator

Application Programmer

25 / 50

A collection of related data is

Data

Logical model

Relational model

Database

26 / 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

27 / 50

Which of the following statements is NOT correct?

The functional dependency EmpNo -> DeptNo holds over R.

The functional dependency DeptNo -> ProjNo holds over R.

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

The functional dependency ProjNo -> DeptNo holds over R.

28 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

CHECK

PRIMARY KEY

FOREIGN KEY

29 / 50

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

foreign key

determinant

index

primary key

30 / 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

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

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

31 / 50

Only A

B and C

Only B

A and B

32 / 50

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

A binary relationship

An identifying relationship

A ternary relationship

A recursive relationship

33 / 50

The ER- data model is an example of:

Physical database

Relational database

Conceptual database

Logical database

34 / 50

User rights information is stored in

Buffer

Catalog

Physical database

Logical database

35 / 50

Which of the following is not a benefit of normalization?

Maximize redundancy

Minimize deletion anomolies

Minimize insertion anomolies

Minimize updation anomolies

36 / 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.

37 / 50

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

Non-transitive dependency

Transitive dependency

Any kind of dependency

Full functional dependency

38 / 50

Identify the correct statement.

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.

Entity integrity constraints are specified between weak entities.

39 / 50

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

DBMS

Data

Data model

Database

40 / 50

Which of the following is true about NOT NULL constraint?

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

enforce domain integrity

41 / 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

42 / 50

Identify the correct statement with respect to normalization.

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.

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.

43 / 50

Which of the following is true for the relational model?

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.

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

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

44 / 50

A software package designed to store and manage databases

Database

Data model

DBMS

Data

45 / 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

46 / 50

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

completeness

specialization

inheritance

uniqueness

47 / 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.

48 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

FOREIGN KEY

NOT NULL

CHECK

49 / 50

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

Data processing

User accessible catalog

Authorization service

Recovery service

50 / 50

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

binary

unary

weak

ternary

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