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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.

$$\small{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count}&2&2&2&2&3&2&2&2.2&3
\\\hline\textbf{2 Marks Count}&3&2&3&3&1&2&1&2.3&3
\\\hline\textbf{Total Marks}&8&6&8&8&5&6&\bf{6}&\bf{6.8}&\bf{8}\\\hline
\end{array}}}$$

Recent questions in Databases

0 votes
1 answer
1
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 348 views
1 vote
2 answers
2
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 263 views
0 votes
2 answers
3
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 242 views
0 votes
1 answer
4
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 302 views
3 votes
1 answer
5
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 421 views
1 vote
1 answer
6
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 890 views
0 votes
1 answer
7
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 188 views
2 votes
3 answers
8
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 196 views
0 votes
3 answers
9
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 262 views
3 votes
2 answers
10
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 198 views
0 votes
1 answer
11
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 81 views
1 vote
1 answer
12
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 82 views
0 votes
1 answer
13
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 124 views
0 votes
1 answer
14
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 97 views
0 votes
1 answer
15
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 63 views
0 votes
1 answer
16
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 63 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) REFERENCES EMPLOYEE (EID), ... ) Choose the correct answer from the options given below: $a$ and $b$ only $a$ only $b$ and $c$ only $c$ only
asked Nov 20, 2020 in Databases jothee 62 views
2 votes
5 answers
18
Every Boyce-Codd Normal Form (BCNF) decomposition is dependency preserving not dependency preserving need be dependency preserving none of these
asked Apr 2, 2020 in Databases Lakshman Patel RJIT 649 views
2 votes
2 answers
19
A functional dependency of the form $x\to y$ is trivial if $y\subseteq x$ $y\subset x$ $x\subseteq y$ $x\subset y\:\text{and}\:y\subset x$
asked Apr 2, 2020 in Databases Lakshman Patel RJIT 852 views
1 vote
5 answers
20
A primary key, if combined with a foreign key creates parent child relationship between the tables that connect them many-to-many relationship between the tables that connect them network model between the tables that connect them none of these
asked Apr 2, 2020 in Databases Lakshman Patel RJIT 384 views
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