CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 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.

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.

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

2 / 50

The ER- data model is an example of:

Conceptual database

Logical database

Physical database

Relational database

3 / 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

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

4 / 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)

5 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

FOREIGN KEY

CHECK

NOT NULL

6 / 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.·

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

by creating two separate tables

7 / 50

Identify the correct statement with respect to normalization.

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.

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

8 / 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.

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.

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

9 / 50

A collection of related data is

Logical model

Relational model

Data

Database

10 / 50

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

Concurrency control.

Logical data independence.

Functional dependency

Physical data independence.

11 / 50

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

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.

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

12 / 50

statement among the following on the above diagram.

The diagram depicts existence dependencies.

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

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

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

13 / 50

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

Data model

Database

Data

DBMS

14 / 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

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.

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

15 / 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 DeptNo -> ProjNo holds over R.

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

16 / 50

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

completeness

uniqueness

inheritance

specialization

17 / 50

Which of the following is not true about relational tables?

Each row is unique.

The sequence of rows is significant.

Each column must have a unique name.

Column values are of the same kind.

18 / 50

Which of the following is true about relational schema?

The sequence of rows is significant.

The sequence of columns is significant

Values are atomic.

Contains only derived attributes.

19 / 50

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

Any kind of dependency

Transitive dependency

Full functional dependency

Non-transitive dependency

20 / 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.

Only A

B and C

A and B

Only B

21 / 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 A and B.

Only A.

Only C.

Only B and C.

22 / 50

Which of the following is true for the relational model?

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

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

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

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

23 / 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 specify that primary key values can be composite.

Entity integrity constraints are specified between weak entities.

24 / 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.

25 / 50

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

UNIQUE

NOT NULL

FOREIGN KEY

CHECK

26 / 50

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

determinant

foreign key

index

primary key

27 / 50

Only B

A and B

B and C

Only A

28 / 50

The ER- data model is an example of:

Relational database

Physical database

Conceptual database

Logical database

29 / 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.

30 / 50

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

User accessible catalog

Data processing

Recovery service

Authorization service

31 / 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.

32 / 50

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

hardware

input and output

software

computer infrastructure

33 / 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.

34 / 50

A database system allows the following EXCEPT

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.

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.

35 / 50

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

Ternary

1:01

M:M

1:M

36 / 50

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

Data

Database

Data model

DBMS

37 / 50

Which of the following constraints enforces entity integrity?

FOREIGN KEY

CHECK

PRIMARY KEY

NOT NULL

38 / 50

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

uniqueness

completeness

specialization

inheritance

39 / 50

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

A binary relationship

A recursive relationship

An identifying relationship

A ternary relationship

40 / 50

User rights information is stored in

Buffer

Logical database

Physical database

Catalog

41 / 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

42 / 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.

43 / 50

A software package designed to store and manage databases

Database

DBMS

Data

Data model

44 / 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 an attribute value lies in the given range.

Referential integrity constraints check whether the primary key values are unique.

45 / 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.

46 / 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.

47 / 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.

all tuples in a particular relation may have different attributes.

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

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

48 / 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.

49 / 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)

50 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unauthorised access to data

avoid duplication

avoid inconsistency among data

avoid unnecessary wastage of storage space

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