search
Log In

Web Page

ER‐model. Relational model:Relational algebra, Tuple calculus, SQL. Integrity constraints, Normal forms. File organization, Indexing (e.g., B and B+ trees). Transactions and concurrency control.

$$\scriptsize{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}&\textbf{2021-1}&\textbf{2021-2}&\textbf{2020}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count}&2&1&2&2&2&2&2&3&2&1&2&3
\\\hline\textbf{2 Marks Count}&3&3&3&3&2&3&3&1&2&1&2.5&3
\\\hline\textbf{Total Marks}&8&7&8&8&6&8&8&5&6&\bf{6}&\bf{7.1}&\bf{8}\\\hline
\end{array}}}$$

Recent questions in Databases

0 votes
1 answer
1
Given two tables EMPLOYEE (EID, ENAME, DEPTNO) DEPARTMENT (DEPTNO, DEPTNAME) Find the most appropriate statement of the given query: Select count (*) total' from EMPLOYEE where DEPTNO IN (D1,D2) group by DEPTNO having count (*) >5 Total number of employees in each ... $>5$ Display total number of employees in both departments $D1$ and $D2$ The output of the query must have at least two rows
asked May 12 in Databases soujanyareddy13 140 views
0 votes
2 answers
2
Find minimum number of tables required for converting the following entity relationship diagram into relational database? $2$ $4$ $3$ $5$
asked May 12 in Databases soujanyareddy13 188 views
1 vote
5 answers
3
For a $B^+$ - tree of order $d$ with $n$ leaf nodes, the number of nodes accessed during a search is $O(\_)$.
asked May 3 in Databases gatecse 272 views
5 votes
5 answers
4
Consider the following statements $S1$ and $S2$ about the relational data model: $S1$: A relation scheme can have at most one foreign key. $S2$: A foreign key in a relation scheme $R$ cannot be used to refer to tuples of $R.$ Which one of the following choices is correct? Both $S1$ and $S2$ are true $S1$ is true and $S2$ is false $S1$ is false and $S2$ is true Both $S1$ and $S2$ are false
asked Feb 18 in Databases Arjun 1.5k views
2 votes
1 answer
5
A data file consisting of $1,50,000$ student-records is stored on a hard disk with block size of $4096$ bytes. The data file is sorted on the primary key $\textrm{RollNo}$. The size of a record pointer for this disk is $7$ bytes. Each student-record has ... disk. Assume that the records of data file and index file are not split across disk blocks. The number of blocks in the index file is ________
asked Feb 18 in Databases Arjun 1.1k views
2 votes
2 answers
6
The relation scheme given below is used to store information about the employees of a company, where $\textsf{empId}$ is the key and $\textsf{deptId}$ indicates the department to which the employee is assigned. Each employee is assigned to exactly ... than the average salary of employees in the department employees in the company female employees in the department female employees in the company
asked Feb 18 in Databases Arjun 723 views
0 votes
2 answers
7
Let $S$ be the following schedule of operations of three transactions $T_1$, $T_2$ and $T_3$ in a relational database system: $R_2(Y), R_1(X), R_3(Z), R_1(Y)W_1(X), R_2(Z), W_2(Y), R_3(X), W_3(Z)$ Consider the statements $P$ and $Q$ below: $P$: $S$ is conflict- ... correct? Both $P$ and $Q$ are true $P$ is true and $Q$ is false $P$ is false and $Q$ is true Both $P$ and $Q$ are false
asked Feb 18 in Databases Arjun 1k views
1 vote
1 answer
8
Suppose the following functional dependencies hold on a relation $U$ with attributes $P,Q,R,S$, and $T$: $P \rightarrow QR$ $RS \rightarrow T$ Which of the following functional dependencies can be inferred from the above functional dependencies? $PS \rightarrow T$ $R \rightarrow T$ $P \rightarrow R$ $PS \rightarrow Q$
asked Feb 18 in Databases Arjun 1.2k views
5 votes
2 answers
9
Suppose a database system crashes again while recovering from a previous crash. Assume checkpointing is not done by the database either during the transactions or during recovery. Which of the following statements is/are correct? The same undo and redo list ... any further All the transactions that are already undone and redone will not be recovered again The database will become inconsistent
asked Feb 18 in Databases Arjun 1.4k views
5 votes
2 answers
10
A relation $r(A, B)$ in a relational database has $1200$ tuples. The attribute $A$ has integer values ranging from $6$ to $20$, and the attribute $B$ has integer values ranging from $1$ to $20$. Assume that the attributes $A$ and $B$ are independently distributed. The estimated number of tuples in the output of $\sigma _{(A>10)\vee(B=18)}(r)$ is ____________.
asked Feb 18 in Databases Arjun 2.1k views
1 vote
2 answers
11
The following relation records the age of $500$ employees of a company, where $empNo$ (indicating the employee number) is the key: $empAge(\underline{empNo},age)$ ... one other employee Employee numbers of all employees whose age is not the minimum Employee numbers of all employees whose age is the minimum
asked Feb 18 in Databases Arjun 862 views
3 votes
3 answers
12
Let $r_i(z)$ and $w_i(z)$ denote read and write operations respectively on a data item $z$ by a transaction $T_i$. Consider the following two schedules. $S_1: r_1(x)r_1(y)r_2(x)r_2(y)w_2(y)w_1(x)$ ... $S_2$ is conflict serializable Both $S_1$ and $S_2$ are conflict serializable Niether $S_1$ nor $S_2$ is conflict serializable
asked Feb 18 in Databases Arjun 790 views
2 votes
5 answers
13
Consider the relation $R(P,Q,S,T,X,Y,Z,W)$ with the following functional dependencies. $PQ\rightarrow X;\quad P\rightarrow YX;\quad Q\rightarrow Y; \quad Y\rightarrow ZW$ Consider the decomposition of the relation $R$ into the constituent relations according to ... , but $D_2$ is a lossless decomposition Both $D_1$ and $D_2$ are lossless decompositions Both $D_1$ and $D_2$ are lossy decompositions
asked Feb 18 in Databases Arjun 1.3k views
3 votes
2 answers
14
Consider a relational schema $S=(U,V,W,X,Y,Z)$ on which the following functional dependencies hold: $(U \rightarrow V, VW \rightarrow X, Y \rightarrow W, X \rightarrow U)$ Which are the candidate keys among following options? $UY, VY$ $UY, VY, XY$ $UYZ, VYZ, VWZ$ $UYZ, VYZ, XYZ$
asked Nov 20, 2020 in Databases jothee 449 views
0 votes
1 answer
15
In the context of concurrency control, a given pair of operations in a schedule is called conflict schedule if At least one of the operations is write operation Both the operations are performed on the same data item Both the operations are performed by different transactions Both the operations are performed on different ... $(b)$ and $(c)$ only $(a)$, $(c)$ and $(d)$ only $(c)$ and $(d)$ only
asked Nov 20, 2020 in Databases jothee 191 views
1 vote
1 answer
16
Match $\text{List I}$ with $\text{List II}$ Choose the correct answer from the options given below: $A-II, B-IV, C-III, D-I$ $A-IV, B-I, C-II, D-III$ $A-II, B-I, C-IV, D-III$ $A-III, B-IV, C-I, D-II$
asked Nov 20, 2020 in Databases jothee 174 views
0 votes
1 answer
17
Consider the following table structures related to a university for the below question. EMPLOYEE NAME VARCHAR (30) NOT NULL, EID VARCHAR (10) NOT NULL, DEPTNO INT (5) NOT NULL, HODEID VARCHAR (10), SALARY INT (10), PRIMARY KEY (EID), FOREIGN KEY (HODEID) ... 20,30,40); SELECT DISTINCT EMPID FROM PROJECTWORK WHERE PROJNO IN(20,30,40); SELECT DISTINCT EMPID FROM PROJECTWORK WHERE PROJNO=20,30,40;
asked Nov 20, 2020 in Databases jothee 280 views
0 votes
1 answer
18
Consider the following table structures related to a university for the below question. EMPLOYEE NAME VARCHAR (30) NOT NULL, EID VARCHAR (10) NOT NULL, DEPTNO INT (5) NOT NULL, HODEID VARCHAR (10), SALARY INT (10), PRIMARY KEY (EID), FOREIGN KEY (HODEID) REFERENCES ... $II$ are false Statement $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
asked Nov 20, 2020 in Databases jothee 250 views
0 votes
1 answer
19
Consider the following table structures related to a university for the below question. EMPLOYEE NAME VARCHAR (30) NOT NULL, EID VARCHAR (10) NOT NULL, DEPTNO INT (5) NOT NULL, HODEID VARCHAR (10), SALARY INT (10), PRIMARY KEY (EID), FOREIGN KEY (HODEID) REFERENCES EMPLOYEE (EID), ... EID Choose the correct answer from the options given below: $a$ and $b$ only $a$ and $c$ only $b$ only $c$ only
asked Nov 20, 2020 in Databases jothee 168 views
0 votes
1 answer
20
Consider the following table structures related to a university for the below question. EMPLOYEE NAME VARCHAR (30) NOT NULL, EID VARCHAR (10) NOT NULL, DEPTNO INT (5) NOT NULL, HODEID VARCHAR (10), SALARY INT (10), PRIMARY KEY (EID), FOREIGN KEY (HODEID) REFERENCES EMPLOYEE (EID), FOREIGN ... correct answer from the options given below: $a$ and $b$ only $a$ and $c$ only $b$ and $c$ only $a$ only
asked Nov 20, 2020 in Databases jothee 198 views
...