CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

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

FOREIGN KEY

NOT NULL

CHECK

UNIQUE

2 / 50

Which of the following is true about relational schema?

The sequence of columns is significant

Values are atomic.

Contains only derived attributes.

The sequence of rows is significant.

3 / 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 B and C.

Only A.

Only A and B.

Only C.

4 / 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.

5 / 50

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

one process (which represents the entire system)

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

all sources/sinks (external entities)

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

6 / 50

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

Application Programmer

Database Designer

End User

Database Administrator

7 / 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.

By referring to a high level data model, it is possible to understand the data requirements of the users, entity types, relationships and constraints

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

8 / 50

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

completeness

specialization

inheritance

uniqueness

9 / 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

Only B

A and B

10 / 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

enforces the uniqueness of the values in a set of columns

limit the values that can be placed in a column

enforce domain integrity

11 / 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.

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

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

12 / 50

User rights information is stored in

Catalog

Logical database

Physical database

Buffer

13 / 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.

14 / 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.

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

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

15 / 50

The ER- data model is an example of:

Physical database

Conceptual database

Logical database

Relational database

16 / 50

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

completeness

inheritance

specialization

uniqueness

17 / 50

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

hardware

software

computer infrastructure

input and output

18 / 50

Which of the following is true about relational schema?

Values are atomic.

The sequence of columns is significant

Contains only derived attributes.

The sequence of rows is significant.

19 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unnecessary wastage of storage space

avoid inconsistency among data

avoid duplication

avoid unauthorised access to data

20 / 50

Which of the following is not a benefit of normalization?

Minimize updation anomolies

Maximize redundancy

Minimize insertion anomolies

Minimize deletion anomolies

21 / 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.

22 / 50

A collection of related data is

Database

Relational model

Logical model

Data

23 / 50

A software package designed to store and manage databases

DBMS

Database

Data model

Data

24 / 50

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

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.

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

25 / 50

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

A recursive relationship

A ternary relationship

A binary relationship

An identifying relationship

26 / 50

Which of the following constraints enforces entity integrity?

CHECK

NOT NULL

PRIMARY KEY

FOREIGN KEY

27 / 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.

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

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

28 / 50

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.

29 / 50

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

Logical data independence.

Functional dependency

Physical data independence.

Concurrency control.

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

Authorization service

Recovery service

31 / 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

32 / 50

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

Non-transitive dependency

Any kind of dependency

Transitive dependency

Full functional dependency

33 / 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

34 / 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, DeptNo) -> ProjNo holds over R.

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

35 / 50

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

binary

unary

weak

ternary

36 / 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.

37 / 50

Structural constraints of a relationship type refer to

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.

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.

38 / 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

39 / 50

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

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.

unique identifier for a row within a database table.

40 / 50

A and B

B and C

Only A

Only B

41 / 50

Select the correct statement among the following.

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

When different entity types participate only once in a single relationship type it is called a recursive relationship

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

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

42 / 50

A database system allows the following EXCEPT

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.

integration of data across multiple applications into a single application

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

43 / 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.

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.

44 / 50

The ER- data model is an example of:

Conceptual database

Physical database

Relational database

Logical database

45 / 50

User rights information is stored in

Logical database

Catalog

Buffer

Physical database

46 / 50

Structural constraints of a relationship type refer to

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.

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.

47 / 50

Which of the following is not true about relational tables?

Each column must have a unique name.

Each row is unique.

The sequence of rows is significant.

Column values are of the same kind.

48 / 50

Which of the following statements is NOT correct?

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.

The functional dependency ProjNo -> DeptNo holds over R.

49 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

CHECK

PRIMARY KEY

FOREIGN KEY

50 / 50

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

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)

one process (which represents the entire system)

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The average score is 22%