CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

A software package designed to store and manage databases

DBMS

Data model

Database

Data

2 / 50

Controlling redundancy in a database management system DOES NOT help to

avoid duplication

avoid unnecessary wastage of storage space

avoid inconsistency among data

avoid unauthorised access to data

3 / 50

Which of the following is true about relational schema?

Contains only derived attributes.

Values are atomic.

The sequence of columns is significant

The sequence of rows is significant.

4 / 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 each table into three

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

5 / 50

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

computer infrastructure

software

input and output

hardware

6 / 50

The ER- data model is an example of:

Conceptual database

Logical database

Physical database

Relational database

7 / 50

User rights information is stored in

Buffer

Logical database

Physical database

Catalog

8 / 50

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

Every non-key attribute is partially dependent on super key

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.

9 / 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 are specified between weak entities.

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

10 / 50

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

unique identifier for a row within a database table.

limit the values that can be placed in a column.

enforces that the column will only accept null values.

allow any actions that would destroy links between tables

11 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

CHECK

NOT NULL

FOREIGN KEY

12 / 50

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

FOREIGN KEY

NOT NULL

UNIQUE

CHECK

13 / 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.

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.

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

14 / 50

Which of the following constraints enforces entity integrity?

FOREIGN KEY

CHECK

PRIMARY KEY

NOT NULL

15 / 50

Which of the following statements is NOT correct?

The functional dependency EmpNo -> DeptNo holds over R.

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.

16 / 50

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

An identifying relationship

A binary relationship

A ternary relationship

A recursive relationship

17 / 50

Which of the following is not a benefit of normalization?

Minimize deletion anomolies

Maximize redundancy

Minimize insertion anomolies

Minimize updation anomolies

18 / 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

19 / 50

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

Data

Database

DBMS

Data model

20 / 50

Select the correct statement about the ANSI/SPARC architecture.

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.

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.

21 / 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 B

Only A

22 / 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

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.

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

23 / 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.

Physical data independence.

Functional dependency

24 / 50

Which of the following is true about NOT NULL constraint?

enforce domain integrity

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

25 / 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.

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.

A logical record is concerned with efficient storage of information in the secondary storage devices.

26 / 50

A collection of related data is

Relational model

Data

Logical model

Database

27 / 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.

28 / 50

Identify the INCORRECT statement among the given

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

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.

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

29 / 50

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

uniqueness

inheritance

specialization

completeness

30 / 50

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

Transitive dependency

Non-transitive dependency

Full functional dependency

Any kind of dependency

31 / 50

Which of the following is true about relational schema?

The sequence of columns is significant

Contains only derived attributes.

Values are atomic.

The sequence of rows is significant.

32 / 50

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

inheritance

uniqueness

specialization

completeness

33 / 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.

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

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

34 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

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.

35 / 50

Identify the correct statement.

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.

Referential integrity constraints are specified between entities having recursive relationships.

36 / 50

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

Data processing

Authorization service

User accessible catalog

Recovery service

37 / 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

Instructor ÷ Student

Student – Instructor

38 / 50

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

M:M

Ternary

1:M

1:01

39 / 50

Which of the following functions are NOT performed by a database administrator?

Communicating with database users

Establishing standards and procedures for database systems

Allocation of storage locations and data structures

Planning, designing and implementing database systems

40 / 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 DeptNo -> ProjNo holds over R.

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

41 / 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

42 / 50

Which of the following is correct?

The relation Interview is in 3NF

The FD3 violates 3NF.

The FD2 violates 2NF.

The relation Interview is in BCNF.

43 / 50

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

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

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.

44 / 50

statement among the following on the above diagram.

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

The diagram depicts existence dependencies.

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

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

45 / 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.

46 / 50

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

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

one process (which represents the entire system)

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

all sources/sinks (external entities)

47 / 50

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

ternary

unary

weak

binary

48 / 50

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

foreign key

determinant

primary key

index

49 / 50

Which of the following is not true about relational tables?

The sequence of rows is significant.

Each column must have a unique name.

Each row is unique.

Column values are of the same kind.

50 / 50

Identify the correct statement with respect to normalization.

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

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

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.

Your score is

The average score is 22%