List of top DBMS Questions asked in GATE Computer Science and Information Technology

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}