CS403 Midterm Online Quiz

2 votes, 5 avg

CS403-Midterm

1 / 50

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

Functional dependency

Logical data independence.

Physical data independence.

Concurrency control.

2 / 50

Identify the correct statement.

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.

When entity integrity rules are enforced, a tuple in one relation that refers to another relation must refer to an existing tuple.

3 / 50

Which of the following is true about relational schema?

The sequence of columns is significant

Contains only derived attributes.

The sequence of rows is significant.

Values are atomic.

4 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

PRIMARY KEY

FOREIGN KEY

CHECK

5 / 50

Identify the correct statement with respect to normalization.

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.

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.

6 / 50

Which of the following is correct?

The relation Interview is in 3NF

The relation Interview is in BCNF.

The FD2 violates 2NF.

The FD3 violates 3NF.

7 / 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.

8 / 50

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

weak

binary

unary

ternary

9 / 50

Which of the following is true about NOT NULL constraint?

limit the values that can be placed in a column

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

10 / 50

Which of the following constraints enforces entity integrity?

NOT NULL

FOREIGN KEY

PRIMARY KEY

CHECK

11 / 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.

12 / 50

statement among the following on the above diagram.

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

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

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

The diagram depicts existence dependencies.

13 / 50

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

UNIQUE

CHECK

NOT NULL

FOREIGN KEY

14 / 50

Which of the following is not a benefit of normalization?

Minimize updation anomolies

Maximize redundancy

Minimize insertion anomolies

Minimize deletion anomolies

15 / 50

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

allow any actions that would destroy links between tables

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.

16 / 50

The ER- data model is an example of:

Relational database

Conceptual database

Logical database

Physical database

17 / 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.

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.

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.

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

20 / 50

Which of the following statements is NOT correct?

The functional dependency ProjNo -> DeptNo holds over R.

The functional dependency DeptNo -> ProjNo holds over R.

The functional dependency EmpNo -> DeptNo holds over R.

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

21 / 50

Which of the following constraints enforces entity integrity?

FOREIGN KEY

NOT NULL

PRIMARY KEY

CHECK

22 / 50

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

uniqueness

specialization

completeness

inheritance

23 / 50

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

The domain of attribute must include only atomic values.

Every non-key attribute is partially dependent on super key

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

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

24 / 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)

25 / 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 check whether the primary key values are unique.

Referential integrity constraints are specified between entities having recursive relationships.

26 / 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.

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

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.

27 / 50

A relation (from the relational database model) consists of a set of tuples, which implies that

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.

all tuples in a particular relation may have different attributes.

28 / 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

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

29 / 50

User rights information is stored in

Catalog

Buffer

Physical database

Logical database

30 / 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.

31 / 50

Structural constraints of a relationship type refer to

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.

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.

32 / 50

Identify the correct statement.

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

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.

33 / 50

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

Database

DBMS

Data

Data model

34 / 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

35 / 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

36 / 50

User rights information is stored in

Buffer

Catalog

Logical database

Physical database

37 / 50

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

all sources/sinks (external entities)

one process (which represents the entire system)

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

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

38 / 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 B

A and B

B and C

Only A

39 / 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 FD2 violates 2NF.

The relation Interview is in BCNF.

The relation Interview is in 3NF

40 / 50

A collection of related data is

Relational model

Database

Logical model

Data

41 / 50

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

input and output

computer infrastructure

software

hardware

42 / 50

The ER- data model is an example of:

Conceptual database

Logical database

Physical database

Relational database

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

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.

45 / 50

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

A recursive relationship

An identifying relationship

A ternary relationship

A binary relationship

46 / 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.

47 / 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.

48 / 50

Which of the following is true about relational schema?

Contains only derived attributes.

The sequence of columns is significant

The sequence of rows is significant.

Values are atomic.

49 / 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.

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

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

50 / 50

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

uniqueness

inheritance

completeness

specialization

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