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S: r3(x) r3(y) w3(x) W2(x) r1(x) w2(y) w3(y) w1(y) How many serial schedules are not view equal to schedule S?

saisri asked in Databases Mar 24

by saisri

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1 answer

2

Explain why BCNF is said to be improved 3NF.

prasantkr.singh answered in Databases Mar 17

by prasantkr.singh

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File organisation and indexing (DBMS)

Suryadip asked in Databases Mar 9

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2 votes

2 answers

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GATE CSE 2024 | Set 2 | Question: 16
Which of the following file organizations is/are $\text{I/O}$ efficient for the scan operation in $\text{DBMS}$? Sorted Heap Unclustered tree index Unclustered hash index

sanjeet24 answered in Databases Mar 5

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Çșȇ ʛấẗẻ asked in Databases Feb 24

by Çșȇ ʛấẗẻ

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Çșȇ ʛấẗẻ asked in Databases Feb 24

by Çșȇ ʛấẗẻ

67 views

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NPTEL DBMS (Introduction to Database systems)course Assignment 10: Topic Database Indexing
Use the following information to answer Questions 7 and 8. A sorted file has the following details: Number of records = 13,10,720; record length = 200 bytes; size of the primary key field = 13 bytes; size of ... of blocks in the first level index file is: a)131072 b)1311 c)1310 d)1286 Accepted Answers: 1286

RishabhSahu325 asked in Databases Feb 22

by RishabhSahu325

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3 answers

8

GATE CSE 2024 | Set 1 | Question: 34
The symbol $\rightarrow$ indicates functional dependency in the context of a relational database. Which of the following options is/are TRUE? $(X, Y) \rightarrow(Z, W)$ implies $X \rightarrow(Z, W)$ $(X, Y) \rightarrow(Z, W)$ ... $(X, W) \rightarrow Z$ $(X \rightarrow Y$ and $Y \rightarrow Z)$ implies $X \rightarrow Z$

GauravRajpurohit answered in Databases Feb 18

by GauravRajpurohit

2.0k views

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2 answers

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GATE DS&AI 2024 | Question: 21
Consider the following two tables named Raider and Team in a relational database maintained by a Kabaddi league. The attribute ID in table Team references the primary key of the Raider table, ID. Raider ID Name Raids RaidPoints $1$ Arjun $200$ $250$ $2$ ... Jaipur" AND RaidPoints > 200; The number of rows returned by this query is $\_\_\_\_\_\_\_\_$.

Hira Thakur answered in Databases Feb 17

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1 answer

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GATE DS&AI 2024 | Question: 36
Given the relational schema $R=(U, V, W, X, Y, Z)$ and the set of functional dependencies: \[ \{U \rightarrow V, U \rightarrow W, W X \rightarrow Y, W X \rightarrow Z, V \rightarrow X\} \] Which of the following functional dependencies can be derived from the above set? $V W \rightarrow Y Z$ $W X \rightarrow Y Z$ $V W \rightarrow U$ $V W \rightarrow Y$

Hira Thakur answered in Databases Feb 17

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2 votes

3 answers

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GATE CSE 2024 | Set 1 | Question: 11
In a $\mathrm{B}+$ tree, the requirement of at least half-full $(50 \%)$ node occupancy is relaxed for which one of the following cases? Only the root node All leaf nodes All internal nodes Only the leftmost leaf node

KASHIF_RAHMAN answered in Databases Feb 17

by KASHIF_RAHMAN

2.0k views

1 vote

2 answers

12

GATE CSE 2024 | Set 1 | Question: 10
Let $\mathrm{S}$ be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following $\mathrm{ER}$ diagrams CORRECTLY represents $\mathrm{S}$? $\text{(i)}$ $\text{(ii)}$ $\text{(iii)}$ $\text{(iv)}$

KASHIF_RAHMAN answered in Databases Feb 17

by KASHIF_RAHMAN

1.9k views

3 votes

2 answers

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GATE CSE 2024 | Set 1 | Question: 12
Which of the following statements about a relation $\mathbf{R}$ in first normal form $\text{(1NF)}$ is/are TRUE? $\mathbf{R}$ can have a multi-attribute key $\mathbf{R}$ cannot have a foreign key $\mathbf{R}$ cannot have a composite attribute $\mathbf{R}$ cannot have more than one candidate key

iarpitmishra answered in Databases Feb 17

by iarpitmishra

3.3k views

1 vote

1 answer

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GATE CSE 2024 | Set 1 | Question: 36
Consider the following read-write schedule $\text{S}$ over three transactions $T_{1}, T_{2}$, and $T_{3}$ ... to $\text{S}$? $T_{1} T_{2} T_{3}$ $T_{1} T_{3} T_{2}$ $T_{3} T_{2} T_{1}$ $T_{3} T_{1} T_{2}$

Hira Thakur answered in Databases Feb 16

2.1k views

2 votes

1 answer

15

GATE CSE 2024 | Set 2 | Question: 35
The relation schema, Person (pid, city), describes the city of residence for every person uniquely identified by pid. The following relational algebra operators are available: selection, projection, cross product, and rename. To find the list of cities ... above operators, the minimum number of cross product operations that must be used is $1$ $2$ $3$ $4$

Deepak Poonia answered in Databases Feb 16

by Deepak Poonia

1.9k views

1 vote

1 answer

16

GATE CSE 2024 | Set 2 | Question: 17
Which of the following statements about the Two Phase Locking ($2 \mathrm{PL}$) protocol is/are TRUE? $2 \mathrm{PL}$ permits only serializable schedules With $2 \mathrm{PL}$, a transaction always locks the data item being read or ... , no more locks on any data item can be obtained inside that transaction A deadlock is possible with $2 \mathrm{PL}$

supreetshukla answered in Databases Feb 16

by supreetshukla

1.7k views

1 vote

1 answer

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GATE CSE 2024 | Set 2 | Question: 46
A functional dependency $F: X \rightarrow Y$ is termed as a useful functional dependency if and only if it satisfies all the following three conditions: $\text{X}$ is not the empty set. $\text{Y}$ is not the empty set. Intersection ... set. For a relation $\text{R}$ with $4$ attributes, the total number of possible useful functional dependencies is __________.

supreetshukla answered in Databases Feb 16

by supreetshukla

1.5k views

1 vote

2 answers

18

GATE CSE 2024 | Set 2 | Question: 9
Once the $\text{DBMS}$ informs the user that a transaction has been successfully completed, its effect should persist even if the system crashes before all its changes are reflected on disk. This property is called durability atomicity consistency isolation

Deepak Poonia answered in Databases Feb 16

by Deepak Poonia

1.9k views

1 vote

1 answer

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GATE CSE 2024 | Set 1 | Question: 25
Consider the following two relations, $R(A, B)$ and $S(A, C)$: $R$ $A$ $B$ $10$ $20$ $20$ $30$ $30$ $40$ $30$ $50$ $50$ $95$ $S$ $A$ $C$ $10$ $90$ $30$ $45$ $40$ $80$ The total number of tuples obtained by evaluating the following expression $\sigma_{B<C}\left(R \bowtie_{R . A=S . A} S\right)$ is ___________.

Hira Thakur answered in Databases Feb 16

1.6k views

1 vote

1 answer

20

GATE CSE 2024 | Set 2 | Question: 10
In the context of owner and weak entity sets in the $\text{ER}$ (Entity-Relationship) data model, which one of the following statements is TRUE? The weak entity set MUST have total participation in the identifying ... in the identifying relationship Neither weak entity set nor owner entity set MUST have total participation in the identifying relationship

supreetshukla answered in Databases Feb 16

by supreetshukla

1.7k views

6 votes

3 answers

21

GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 14
A B-Tree of order $m$ is an $m$-way search tree. What is the minimum number of keys that can be stored on the leaf level of a B-Tree of order 20 with 3 levels? (Note: the root of a tree counts as its first level)

Praveenjha802 answered in Databases Feb 7

by Praveenjha802

630 views

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1 answer

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Memory Based GATE DA 2024 | Question: 16
Consider a relation R: \[ \begin{aligned} & R(U, V, W, X, Y, Z) \\ & F=\left\{ \begin{array}{l} U \rightarrow V \\ U \rightarrow W \\ WX \rightarrow Y \\ WX \rightarrow Z \\ V \rightarrow X \end ... be deduced. Which of the following options is correct? $VW \rightarrow U$ $VW \rightarrow Y$ $VW \rightarrow YZ$ $WX \rightarrow YZ$

Lakshmi Narayana404 answered in Databases Feb 6

by Lakshmi Narayana404

175 views

4 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 13
Division operator in relational algebra is appropriate to handle which of the following query types? employees work on at most one of the critical projects employees work on any one of the critical projects employees work on at least one of the critical projects employees work on all the critical projects

GO Classes answered in Databases Feb 5

336 views

4 votes

0 answers

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GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 40
Consider the following schema (primary keys are underlined): Which of the following queries returns the department numbers of those departments for which there are no courses being offered?

GO Classes asked in Databases Feb 5

278 views

9 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 41
Consider the following lock requests in the Table below. And note that: $\mathrm{S}(\cdot)$ and $\mathrm{X}(\cdot)$ stand for 'shared lock' and 'exclusive lock', respectively. $T_1, T_2, T_3, T_4$, and $T_5$ represent five ... dead('-'). Select all that are correct. At t3: a At t6: b At t7: a At t8: -

GO Classes answered in Databases Feb 5

666 views

6 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 50
Consider the following database relation: $\mathrm{R}=(\mathrm{SFLNGCRW} \mathrm{H})=(\mathrm{S}$ : SID, F: First Name, L: Last Name, N: Number of Units, G: GPA, C: Course (of teaching), R ... only one applied? SID determines Rating Rating determines Wage Rating determines Course Rating and First Name determine Wage and Hours of Work

GO Classes answered in Databases Feb 5

296 views

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Memory Based GATE DA 2024 | Question: 17
Consider the following SQL query: \[ \begin{aligned} &\text{SELECT * FROM Raider, Team} \\ &\text{WHERE Raider.id = Team.id} \\ &\text{AND City = 'Jaipur'} \\ &\text{AND Raid_points \textgreater 200; ... {aligned} \] Determine the number of rows returned by the SQL query, given the conditions specified for the City and Raid points.

GO Classes asked in Databases Feb 4

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0 answers

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Memory Based GATE DA 2024 | Question: 47
You are given three tables: `team`, `table1`, and `table2`. To find the names of all players in the team who are either present in `table1` or `table2`, consider the following relational algebra queries: \(\Pi_{\text{{PlayerName}}}(\text{{team}}) \,/\, \ ... text{{Name}}}(\text{{table1}} \cap \text{{table2}}) \,/\, \Pi_{\text{{PlayerName}}}(\text{{team}})\)

GO Classes asked in Databases Feb 4

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0 answers

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Memory Based GATE DA 2024 | Question: 58
DBMS question: One SQL query is given. Based on the query which data structure can be used involving hashing, B+ tree, etc?

GO Classes asked in Databases Feb 4

116 views

1 vote

2 answers

30

Consider a schema R(A, B, C, D, E, F) and functional dependencies A → B, C → D, and E → F. The number of superkeys of this schema is ____

amityadav answered in Databases Feb 3

195 views

5 votes

5 answers

31

ISRO2020-51
The SQL query SELECT columns FROM TableA RIGHT OUTER JOIN TableB ON A.columnName = B.columnName WHERE A.columnName IS NULL returns the following: All rows in Table $\text{B}$, which meets equality condition above and, none from Table $\text{A}$ which meets the ... in Table $\text{B}$, which meets the equality condition All rows in Table $\text{A}$, which meets the equality condition

satyaAchar answered in Databases Feb 1

3.5k views

3 votes

2 answers

32

GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 65
Let $r(X, Y)$ and $s(Y)$ be two relations. What is returned by the following relational algebra query? Values of $r.X$ which are related to every value of $s.Y$. Values of $r.Y$ which are related to every value of $s.Y$. ... which are not related to some value of $s.Y$. Values of $r.X$ which are not related to any value of $s.Y$.

Aaveg537 answered in Databases Jan 29

455 views

3 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 31
Let $\text{R}_1, \text{R}_2, \ldots,\text{ }R_n$ be a decomposition of schema $\text{U}$. Let $u(\text{U})$ be a relation, and let $r_i=\Pi_{\text{R}_i}(u)$ ... $u=r_1 \bowtie r_2 \bowtie r_3 \bowtie r_4 \bowtie . . r_n$ None of the above

Deepak Poonia answered in Databases Jan 28

by Deepak Poonia

358 views

0 votes

1 answer

34

please explain this sql question and how do we get the answer?

GauravRajpurohit answered in Databases Jan 28

by GauravRajpurohit

142 views

3 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 32
The order of a leaf node in a $\text{B tree}$ is the maximum number of (value, data record pointer) pairs it can hold. Given that the block size is $1 \mathrm{~K}$ bytes, data record pointer is $7$ bytes long, the value field is $9$ bytes long and a block pointer is $6$ bytes long, what is the order of the leaf node?

GO Classes answered in Databases Jan 28

437 views

3 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 33
Consider the following two schedules consisting to two transaction $\mathrm{T}_1$ and $\mathrm{T}_2$ : Which of the following is/are true about these schedules? Both $\mathrm{S}_1$ and $\mathrm{S}_2$ are ... and also conflict serializable. $\mathrm{S}_1$ and $\mathrm{S}_2$ are neither conflict equivalent nor conflict serializable.

GO Classes answered in Databases Jan 28

238 views

5 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 64
Consider the following schema: The primary key fields are underlined, and the domain of each field is listed after the field name. Assume there are no NULL values in any column of any relation and every relation has at least one tuple. ... who have a rating of $10 $ OR have reserved boat $104.$ All sids of sailor table Empty set.

GO Classes answered in Databases Jan 28

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