List of top DBMS Questions

An application executes \( 6.4 \times 10^8 \) number of instructions in 6.3 seconds. There are four types of instructions, the details of which are given in the table. The duration of a clock cycle in nanoseconds is ____________. (rounded off to one decimal place)

Consider the following relational schema: 

Which of the following options is/are correct SQL query/queries to retrieve the names of the students enrolled in course number (i.e., courseno) 1470?

Consider the database transactions \( T1 \) and \( T2 \), and data items \( X \) and \( Y \). Which of the schedule(s) is/are conflict serializable? 

An audit of a banking transactions system has found that on an earlier occasion, two joint holders of account \( A \) attempted simultaneous transfers of Rs. 10000 each from account \( A \) to account \( B \). Both transactions read the same value, Rs. 11000, as the initial balance in \( A \) and were allowed to go through. \( B \) was credited Rs. 10000 twice. \( A \) was debited only once and ended up with a balance of Rs. 1000. Which of the following properties is/are certain to have been violated by the system?
For a direct-mapped cache, 4 bits are used for the tag field and 12 bits are used to index into a cache block. The size of each cache block is one byte. Assume that there is no other information stored for each cache block. Which ONE of the following is the CORRECT option for the sizes of the main memory and the cache memory in this system (byte addressable), respectively?
Consider two relations describing teams and players in a sports league:

teams(tid, tname): tid and tname are team-id and team-name, respectively.
players(pid, pname, tid): pid, pname, and tid denote player-id, player-name, and the team-id of the player, respectively.

Which one of the following tuple relational calculus queries returns the name of the players who play for the team having tname as 'MI'?
Which one of the following regular expressions is equivalent to the language accepted by the DFA given below? \begin{center} \includegraphics[width=6cm]{22.png} \end{center}
Match List - I with List - II.

List - I

List - II

(A)Data Base Schema(I)Limitation on the type of data
(B)Data Constraint(II)Data about data
(C)Meta Data(III)State or snapshot of the database
(D)Database Instance(IV)Visual or logical architecture

Choose the correct answer from the options given below:
If on applying a hash function, every items of a list maps to unique index in the hash table it is called.
HAVING clause in SQL is used to specify conditions on the rows with
Consider the following statements:
(A) Each attribute in a relation has a unique name
(B) All data values in an attribute must be from the same domain
(C) A special value NULL is used to represent values that are unknown
(D) A database constraint allow different types of data to inserted into the table
Choose the correct answer from the options given below:
Which of the following statements are true?
(A) Where condition in SQL can include aggregate functions.
(B) Having condition in SQL can include aggregate functions.
(C) SQL set operators tend to combine columns from two or more tables.
(D) GROUP BY function is used to group rows of a table that contain the same values in a specified column.
(E) Minus operator is also known as intersect operator.
Choose the correct answer from the options given below:
____ is the logical architecture of a Database while ____ after loading data in a database.
File system becomes difficult to handle when number of files increases and volume of data also grows. Identify the limitations of file system.
Consider the table below: UNIFORM
VcodeVnameVcolor
1ShirtWhite
2PantGrey
3SkirtGrey

Which of the following tuples cannot be inserted into the UNIFORM table ?
Identify the one which is not an online database.
Which of the following is a disadvantage of using questionnaire method of data collection?