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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

1 vote
4 answers
1
Every Boyce-Codd Normal Form (BCNF) decomposition is dependency preserving not dependency preserving need be dependency preserving none of these
asked Apr 2 in Databases Lakshman Patel RJIT 350 views
1 vote
1 answer
2
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 in Databases Lakshman Patel RJIT 176 views
0 votes
3 answers
3
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 in Databases Lakshman Patel RJIT 225 views
0 votes
2 answers
4
Assume transaction $A$ holds a shared lock $R.$ If transaction $B$ also requests for a shared lock on $R.$ It will result in deadlock situation immediately be granted immediately be rejected be granted as soon as it is released by $A$
asked Apr 1 in Databases Lakshman Patel RJIT 101 views
0 votes
1 answer
5
Given relations $R(w,x)$ and $S(y,z),$ the result of SELECT DISTINCT $w,x$ from $R,S$ $R$ has no duplicates and $S$ is non-empty $R$ and $S$ have no duplicates $S$ has no duplicates and $R$ is non-empty $R$ and $S$ has the same number of tuples
asked Apr 1 in Databases Lakshman Patel RJIT 83 views
0 votes
2 answers
6
For a database relation $R(a,b,c,d)$ where the domains of $a,b,c$ and $d$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold. $a \rightarrow c$ $b \rightarrow d$ The relation is in First normal form but not in second normal form Second normal form but not in third normal form Third normal form None of the above
asked Apr 1 in Databases Lakshman Patel RJIT 71 views
1 vote
1 answer
7
0 votes
1 answer
8
When transaction $Ti$ requests a data item currently held by $Tj,Ti$ is allowed to wait only if it has a timestamp smaller than that of $Tj$ (that is $Ti$ is order than Tj). Otherwise, $Ti$ is rolled back (dies). This is Wait-die Wait-wound Wound-wait Wait
asked Apr 1 in Databases Lakshman Patel RJIT 57 views
0 votes
2 answers
9
When transaction $Ti$ requests a data item currently held by $Tj,Ti$ is allowed to wait only if it has a timestamp smaller than that of $Tj$ (that is $Ti$ is order than Tj). Otherwise, $Ti$ is rolled back (dies). This is Wait-die Wait-wound Wound-wait Wait
asked Apr 1 in Databases Lakshman Patel RJIT 76 views
0 votes
0 answers
10
Given relations $R(w,x)$ and $S(y,z),$ the result of SELECT DISTINCT $w,x$ from $R,S$ $R$ has no duplicates and $S$ is non-empty $R$ and $S$ have no duplicates $S$ has no duplicates and $R$ is non-empty $R$ and $S$ has the same number of tuples
asked Apr 1 in Databases Lakshman Patel RJIT 54 views
0 votes
1 answer
13
Assume transaction $A$ holds a shared lock $R.$ If transaction $B$ also requests for a shared lock on $R.$ It will result in deadlock situation immediately be granted immediately be rejected be granted as soon as it is released by $A$
asked Apr 1 in Databases Lakshman Patel RJIT 49 views
0 votes
1 answer
14
Table employees has $10$ records. It has a non-NULL SALARY column which is also UNIQUE. The SQL statement SELECT COUNT(*) FROM EMPLOYEE WHERE SALARY > ALL (SELECT SALARY FROM EMPLOYEE); $10$ $9$ $5$ $0$
asked Apr 1 in Databases Lakshman Patel RJIT 67 views
1 vote
1 answer
15
0 votes
1 answer
16
Global locks synchronize access to local resources. synchronize access to global resources. are used to avoid local locks. prevent access to global resources.
asked Mar 31 in Databases Lakshman Patel RJIT 75 views
0 votes
1 answer
18
The employee salary should not be greater than Rs.$2000$. This is integrity constraint. referential constraint. over-defined constraint. feasible constraint.
asked Mar 31 in Databases Lakshman Patel RJIT 242 views
0 votes
1 answer
19
The relational algebra expression equivalent to the tuple calculus expression $\{t\mid t ​ \in ​ r \land (t[A]=10 \land t[B]=20)\}$ is $\sigma_{(A=10\:\lor\:B=20)}(r)$ $\sigma_{(A=10)}(r)\cup\sigma_{(B=20)}(r)$ $\sigma_{(A=10)}(r)\cap\sigma_{(B=20)}(r)$ $\sigma_{(A=10)}(r)-\sigma_{(B=20)}(r)$
asked Mar 31 in Databases Lakshman Patel RJIT 131 views
1 vote
2 answers
20
Let $R=(A,B,C,D,E,F)$ be a relation scheme with the following dependencies: $C\to F,E\to a,EC\to D, A\to B$. Which of the following is a key for $R$? $CD$ $EC$ $AE$ $AC$
asked Mar 31 in Databases Lakshman Patel RJIT 143 views
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