Question 1

Given the functional dependencies X ?W; X?Y; Y?Z and Z?PQ Which of the following doesn't hold well?
A)X?Z
B)W?Z
C)X?WY
D)None of the above

Accepted Answer

Given the functional dependencies, we can infer the following:- From X?W and X?Y, it's clear that X functionally determines both W and Y, so X?WY holds true.- Since X?Y and Y?Z, by transitivity, X?Z also holds true.- However, there's no direct or transitive dependency that allows W to determine Z, making W?Z the option that doesn't hold well.

Question 2

An attribute of one table matching the primary key of another table, is called as
A)Foreign key
B)Secondary key
C)Candidate key
D)Composite key

Accepted Answer

A foreign key is an attribute in a relational database table that provides a link between two tables. It is a field (or collection of fields) in one table, that refers to the primary key in another table. The purpose of the foreign key is to ensure referential integrity of the data.

Question 3

A primary key when combined with a foreign key create
A)Parent child relationship between the tables that connect them.
B)Network model between the tables that connect them.
C)Many-to-many relationship between the tables that connect them.
D)None of the above.

Accepted Answer

A primary key and a foreign key together establish a parent-child relationship between the tables that connect them. The primary key exists in the parent table, and the foreign key is in the child table, referencing the primary key to enforce referential integrity.

Question 4

The set of permitted value for each attribute is called its
A)Attribute set
B)Attentive range
C)Domain
D)Group

Accepted Answer

The set of permitted values for each attribute in a database is referred to as its "domain." This term is used to describe the range or set of values that an attribute can legally take.

Question 5

The airline reservation system, the enables are date, flight number, place of departure, destination, type of plane & seats available. The primary key is
A)Flight number
B)Flight number + place of departure
C)Flight number+ date
D)Flight number + destination

Accepted Answer

The primary key must uniquely identify each record. A flight number alone does not suffice because the same flight number can be used on different dates. Combining the flight number with the date ensures each record is unique, as it specifies a particular flight on a specific day.

Question 6

A functional dependency of the form X?Y is trivial if
A)YC= X
B)Y C X
C)X C =Y
D)X C Y and Y C X

Accepted Answer

A functional dependency of the form X → Y is trivial if Y is a subset of X.

Question 7

In transactions, in ACID property A stands for
A)Atomicity
B)Acidity
C)Alphabetically
D)None of the above.

Accepted Answer

Atomicity ensures that each transaction is treated as a single unit, which either succeeds completely or fails completely.

Question 8

Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R.
A)It will result in a deadlock situation.
B)It will immediately be granted.
C)It will immediately be reject

Accepted Answer

Transaction B will immediately be granted a shared lock on R because shared locks are compatible with each other.

Question 9

A schedule S of n transactions is serializable if it is equivalent to some
A)Serial schedule of the same n transactions.
B)Non-serial schedule of the same n transactions.
C)Serial schedule of different n transactions.
D)Non-serial schedule of different n transactions.

Accepted Answer

A schedule is considered serializable if its effect on the database is equivalent to that of some serial schedule of the same transactions. This means the transactions' outcomes are as if they were executed one after the other, without overlapping, ensuring consistency and correctness in a concurrent environment.

Question 10

In two-phase locking protocol.
A)All unlocking operations precede the first lock operation.
B)All locking operations precede the first unlock operation.
C)Locking and unlocking takes place simultaneously.
D)None of the above.

Accepted Answer

In the two-phase locking protocol, all locking operations occur before any unlock operation. This ensures serializability in transaction schedules by preventing any transaction from acquiring new locks once it releases any lock, thus dividing the transaction into two distinct phases: a growing phase where locks are acquired and a shrinking phase where locks are released.

Question 11

Transaction timestamp is:
A)Not unique for each transaction
B)Larger for older transaction
C)Unique identifier assigned to each transaction.
D)None of the above.

Accepted Answer

Transaction timestamp is a unique identifier assigned to each transaction to help in differentiating and managing transactions in a database or transactional system.

Question 12

The granularity of a database item can be chosen to be
A)A whole file
B)A database record
C)The whole database
D)All of the above.

Accepted Answer

The granularity of a database item refers to the level of detail or size of the data item considered for storage and manipulation. It can range from a whole file or database to a more detailed level such as a single record within a database, thus all the options provided are correct.

Question 13

If the complete execution of the transaction(s) takes the database from one consistent state to the other then that property of transaction is called:
A)Isolation
B)Durability
C)Consistency preservation
D)None of the above

Accepted Answer

Consistency preservation is the property of a transaction where if the database was in a consistent state before the transaction, it remains in a consistent state after the transaction is completed. This means that all data integrity constraints are met.

Question 14

Which of the following is not the state that the transaction undergoes?
A)Failed
B)Active
C)Partially committed
D)Non active

Accepted Answer

Transactions typically undergo states such as Active, Partially Committed, and Failed, but "Non active" is not a standard state recognized in transaction state models.

Question 15

Timestamp can be generated by:
A)Counter
B)Current date/time
C)None of the above
D)Both (a) and (b)

Accepted Answer

Timestamps can be generated using both a counter (which increments to track a sequence of events or the passage of time) and the current date/time (to mark when an event occurs in real-world time).

Question 16

Which of the following is the formal process for deciding which attributes should be grouped together in a relation?
A)Normalization
B)Performance Tuning
C)Optimization
D)None of the above

Accepted Answer

Normalization is the formal process used in database design to organize data attributes into relations (tables) based on rules designed to protect the data and to make the database more flexible by eliminating redundancy and inconsistent dependency.

Question 17

Who developed normalization process?
A)C.J. Date
B)E.F. Codd
C)Donald Chamberlain
D)Collin White

Accepted Answer

E.F. Codd developed the normalization process as part of his relational database model to reduce data redundancy and improve data integrity.

Question 18

Who developed the BCNF?
A)Boyd and Cromwell
B)Date and Codd
C)Date and White
D)Boyce and Codd

Accepted Answer

Boyce-Codd Normal Form (BCNF) was developed by Raymond F. Boyce and Edgar F. Codd.

Question 19

What is the expansion of BCNF?
A)Boyd-Cromwell Normal Form
B)Boyce-Codd Normal Form
C)Boyd-Codd Normal Form
D)All of the above

Accepted Answer

Boyce-Codd Normal Form is the correct expansion of BCNF, which is a design principle for relational databases aimed at reducing redundancy and dependency by ensuring that every determinant is a candidate key.

Question 20

Which of the following is true?
A)Normalized data is the best representation of data.
B)Data stored non-redundantly will be accessed faster than data stored many times.
C)Normalized tables are the best way to store data.
D)All of the above

Accepted Answer

Normalization reduces redundancy and improves data integrity, but it may not always be the fastest for data retrieval. The best representation depends on the specific use case.

Quiz 1: Database Management System DBMS: Part A

Given the functional dependencies X ?W; X?Y; Y?Z and Z?PQ Which of the following doesn't hold well?

An attribute of one table matching the primary key of another table, is called as

A primary key when combined with a foreign key create

The set of permitted value for each attribute is called its

The airline reservation system, the enables are date, flight number, place of departure, destination, type of plane & seats available. The primary key is

A functional dependency of the form X?Y is trivial if

In transactions, in ACID property A stands for

Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R.

A schedule S of n transactions is serializable if it is equivalent to some

In two-phase locking protocol.

Transaction timestamp is:

The granularity of a database item can be chosen to be

If the complete execution of the transaction(s) takes the database from one consistent state to the other then that property of transaction is called:

Which of the following is not the state that the transaction undergoes?

Timestamp can be generated by:

Which of the following is the formal process for deciding which attributes should be grouped together in a relation?

Who developed normalization process?

Who developed the BCNF?

What is the expansion of BCNF?

Which of the following is true?