CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 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

2 / 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.

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

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

3 / 50

The ER- data model is an example of:

Conceptual database

Relational database

Logical database

Physical database

4 / 50

Which of the following is true for the relational model?

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.

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

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

5 / 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 are specified on individual relations.

Entity integrity constraints specify that primary key values can be composite.

Entity integrity constraints are specified between weak entities.

6 / 50

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

DBMS

Database

Data

Data model

7 / 50

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

completeness

inheritance

uniqueness

specialization

8 / 50

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

A binary relationship

A ternary relationship

An identifying relationship

A recursive relationship

9 / 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.

10 / 50

User rights information is stored in

Catalog

Logical database

Buffer

Physical database

11 / 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.

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.

12 / 50

Which of the following is not true about relational tables?

The sequence of rows is significant.

Each column must have a unique name.

Column values are of the same kind.

Each row is unique.

13 / 50

Which relational algebra operation could have been applied on the pair of relations Student and Instructor to obtain the above data?

Instructor – Student

Student ∩ Instructor

Student – Instructor

Instructor ÷ Student

14 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

NOT NULL

CHECK

FOREIGN KEY

15 / 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

16 / 50

A collection of related data is

Database

Data

Relational model

Logical model

17 / 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.

18 / 50

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

software

computer infrastructure

hardware

input and output

19 / 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.

Concurrency control.

Functional dependency

Logical data independence.

20 / 50

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

weak

ternary

unary

binary

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

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

22 / 50

B and C

Only A

A and B

Only B

23 / 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.

any user to access all its data.

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

integration of data across multiple applications into a single application

24 / 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 are specified between weak entities.

Entity integrity constraints are specified on individual relations.

Entity integrity constraints specify that primary key values can be composite.

25 / 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.

26 / 50

Which of the following is true about relational schema?

Contains only derived attributes.

The sequence of rows is significant.

The sequence of columns is significant

Values are atomic.

27 / 50

A software package designed to store and manage databases

Data

Database

DBMS

Data model

28 / 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.

29 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid unnecessary wastage of storage space

avoid inconsistency among data

avoid unauthorised access to data

avoid duplication

30 / 50

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

NOT NULL

CHECK

FOREIGN KEY

UNIQUE

31 / 50

Which of the following is not a benefit of normalization?

Minimize updation anomolies

Minimize insertion anomolies

Minimize deletion anomolies

Maximize redundancy

32 / 50

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

M:M

1:01

1:M

Ternary

33 / 50

User rights information is stored in

Buffer

Catalog

Physical database

Logical database

34 / 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.

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

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

35 / 50

Which of the following is true about NOT NULL constraint?

limit the values that can be placed in a column

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

enforce domain integrity

enforces the uniqueness of the values in a set of columns

36 / 50

Which of the following statements is NOT correct?

The functional dependency EmpNo -> DeptNo holds over R.

The functional dependency ProjNo -> DeptNo holds over R.

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

The functional dependency DeptNo -> ProjNo holds over R.

37 / 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.

38 / 50

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

limit the values that can be placed in a column.

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.

39 / 50

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

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

Every non-key attribute is partially dependent on super key

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

The domain of attribute must include only atomic values.

40 / 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.

41 / 50

Which of the following is correct?

The FD3 violates 3NF.

The relation Interview is in BCNF.

The relation Interview is in 3NF

The FD2 violates 2NF.

42 / 50

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

Data

Data model

Database

DBMS

43 / 50

The ER- data model is an example of:

Logical database

Physical database

Conceptual database

Relational database

44 / 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 C.

Only A and B.

Only B and C.

Only A.

45 / 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.

46 / 50

Identify the correct statement.

Referential integrity constraints are specified between entities having recursive relationships.

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

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.

47 / 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

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.

48 / 50

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

Database Administrator

End User

Application Programmer

Database Designer

49 / 50

Which of the following constraints enforces entity integrity?

CHECK

PRIMARY KEY

NOT NULL

FOREIGN KEY

50 / 50

Select the correct statement about the ANSI/SPARC architecture.

The internal level in a database system will definitely be relational.

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.

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