CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

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

by splitting each table into three

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.

using a junction table with the keys from both the tables forming the composite primary key of the junction table.

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.·

using a junction table with the keys from both the tables forming the composite primary key of the junction table.

by creating two separate tables

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

3 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

CHECK

PRIMARY KEY

FOREIGN KEY

4 / 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.

5 / 50

User rights information is stored in

Logical database

Buffer

Catalog

Physical database

6 / 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

enforce domain integrity

limit the values that can be placed in a column

7 / 50

Which of the following constraints enforces entity integrity?

PRIMARY KEY

CHECK

FOREIGN KEY

NOT NULL

8 / 50

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

1:01

M:M

1:M

Ternary

9 / 50

statement among the following on the above diagram.

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

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

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

The diagram depicts existence dependencies.

10 / 50

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

Any kind of dependency

Full functional dependency

Non-transitive dependency

Transitive dependency

11 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

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.

12 / 50

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

limit the values that can be placed in a column.

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

13 / 50

A collection of related data is

Logical model

Data

Database

Relational model

14 / 50

User rights information is stored in

Physical database

Buffer

Logical database

Catalog

15 / 50

The ER- data model is an example of:

Logical database

Relational database

Physical database

Conceptual database

16 / 50

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

completeness

specialization

inheritance

uniqueness

17 / 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.

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.

18 / 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

by splitting each table into three

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

19 / 50

Which of the following constraints enforces entity integrity?

CHECK

PRIMARY KEY

FOREIGN KEY

NOT NULL

20 / 50

Which of the following is correct?

The FD3 violates 3NF.

The FD2 violates 2NF.

The relation Interview is in 3NF

The relation Interview is in BCNF.

21 / 50

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

NOT NULL

UNIQUE

CHECK

FOREIGN KEY

22 / 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 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.

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

23 / 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

24 / 50

Identify the correct statement.

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.

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

25 / 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.

Functional dependency

Concurrency control.

Logical data independence.

26 / 50

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

Database

DBMS

Data

Data model

27 / 50

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

all sources/sinks (external entities)

one process (which represents the entire system)

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

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

28 / 50

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

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

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

29 / 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.

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

all tuples in a relation must be distinct.

30 / 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.

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

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

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

31 / 50

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

computer infrastructure

input and output

hardware

software

32 / 50

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

An identifying relationship

A ternary relationship

A binary relationship

A recursive relationship

33 / 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.

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

34 / 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

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

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

Which of the following is not a benefit of normalization?

Minimize deletion anomolies

Maximize redundancy

Minimize insertion anomolies

Minimize updation anomolies

36 / 50

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

Planning, designing and implementing database systems

Establishing standards and procedures for database systems

Allocation of storage locations and data structures

Communicating with database users

37 / 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 (EmpNo, ProjNo) -> DeptNo holds over R.

The functional dependency ProjNo -> DeptNo holds over R.

38 / 50

Identify the correct statement.

Entity integrity constraints are specified between weak entities.

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.

Entity integrity constraints are specified on individual relations.

39 / 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.

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.

40 / 50

Identify the INCORRECT statement among the given

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.

An entity may be an object with a physical existence like a car, a house or an Employee.

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

41 / 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

Student – Instructor

Instructor ÷ Student

42 / 50

Which of the following statements is NOT correct?

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

The functional dependency EmpNo -> DeptNo holds over R.

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

The functional dependency ProjNo -> DeptNo holds over R.

43 / 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.

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

Normalization is a formal technique that can be used only at the starting phase of the database design.

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

44 / 50

Consider the relation Interview (CandidateNo, InterviewDate, InterviewTime, StaffNo, RoomNo) and the following functional dependencies.
FD1 : CandidateNo, InterviewDate -> InterviewTime, StaffNo, RoomNo
FD2 : RoomNo, InterviewDate, InterviewTime -> StaffNo, CandidateNo
FD3 : StaffNo, InterviewDate -> RoomNo
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.

45 / 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 ProjNo -> DeptNo holds over R.

The functional dependency EmpNo -> DeptNo holds over R.

46 / 50

B and C

A and B

Only B

Only A

47 / 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

48 / 50

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

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)

all sources/sinks (external entities)

49 / 50

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

binary

weak

ternary

unary

50 / 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

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

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

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