Dark Mode

Recent questions and answers in Databases

0 votes

0 answers

1

Subject : Databse Topic: 2pl locking protocol..... If the given schedule is allowed under any 2pl( basic 2pl,strict or rigorous) then it is also allowed in conflict serializble , so if the schedule which is allowed in conflict serializable then also we can say it will be allowed in 2pl?

Ashutosh888 asked in Databases 17 hours ago

12 views

0 votes

1 answer

2

Nielit nov 2018
Consider the following functional dependency in a database A-->B B-->C D-->E E-->D F-->G F-->H (E,F)-->I The relation (E,D,A,B) IS: 2NF 3NF BCNF NONE OF ABOVE

Shivacs61 answered in Databases 6 days ago

227 views

0 votes

1 answer

3

functional dependency
given an instance of relation R(ABC). find all non-trivial FDsare AB->C, AC->B, BC→ A true ??

chinmay_rajpurohit answered in Databases Mar 18

by chinmay_rajpurohit

81 views

0 votes

1 answer

4

Calcutta University Question Paper
Consider a relation r1(A, B, C), r2(C, D, E) and r3(E, G) with primary keys A, C and E respectively. Assume that r1 has 1000 tuples, r2 has 1500 tuples and r3 has 750 tuples. The number of resultant tuple in are

Ujjal roy answered in Databases Mar 16

184 views

1 vote

2 answers

5

NIELIT Scientific Assistant A 2020 November: 97
Domain constraints, functional dependency and referential integrity are special forms of _______ Foreign key Primary key Assertion Referential constraint

Sagnick p answered in Databases Mar 14

172 views

49 votes

5 answers

6

GATE CSE 2002 | Question: 16
For relation R=(L, M, N, O, P), the following dependencies hold: $ M \rightarrow O,$ $NO \rightarrow P,$ $P \rightarrow L$ and $L \rightarrow MN$ R is decomposed into R1 = (L, M, N, P) and R2 = (M, ... above decomposition dependency-preserving? If not, list all the dependencies that are not preserved. What is the highest normal form satisfied by the above decomposition?

diptanshu malviya answered in Databases Mar 13

by diptanshu malviya

12.9k views

3 votes

3 answers

7

GATE CSE 2023 | Question: 6
Which one of the options given below refers to the degree (or arity) of a relation in relational database systems? Number of attributes of its relation schema. Number of tuples stored in the relation. Number of entries in the relation. Number of distinct domains of its relation schema.

Gate Shark answered in Databases Mar 10

1.0k views

0 votes

2 answers

8

Database:
Consider f is AB->C, C->A, BC->D, ACD->B, BE->C, CE->FA, CF->BD, D->E then find the canonical cover.

Bharat Bhushan answered in Databases Mar 10

by Bharat Bhushan

2.9k views

0 votes

1 answer

9

Will not Exist(cc in T1 is not equal to T2) gives TRUE ? , can anyone explain this

Ujjal roy answered in Databases Mar 8

70 views

0 votes

1 answer

10

TestBook TestSeries Finding number of records under join of 2 tables
Assume a relation R' having 200 records. These records are stored in blocks having block factor as 20. Consider another relation S' having 120 records and all these records are stored in 30 blocks. These two tables have to be joined ... the total number of block access required to join R and S ? A. 2430 B. 6010 C. 6120 D. 1230

Ujjal roy answered in Databases Mar 8

74 views

2 votes

2 answers

11

DRDO CSE 2022 Paper 2 | Question: 15 (b)
Answer the following. ___________ removes all the rows of the given table.

wizard_2004 answered in Databases Mar 7

117 views

1 vote

1 answer

12

DBMS
can we make weak entity type as composite attribute of another weak entity type?

KG answered in Databases Mar 6

by KG

128 views

2 votes

2 answers

13

Function Dependency question
Consider a relation R(A,B,C,D,E,F,H) with A as the only key. Assume that the dependencies E->F and C-> DEH hold.on R. 1. Is R in 2NF? If not, decompose to 2NF. 2. is R in 3NF? if not, decompose to 3NF. //What does " with A as the only key" mean ?

rooney answered in Databases Mar 6

by rooney

698 views

0 votes

1 answer

14

#dbms #normalisation
2NF , 3NF, BCNF decomposition allowed if lossless and dependency preserving , both conditions must preserve. Otherwise given decomposition wrong for normal forms. Is this statement correct????

Bharat Bhushan answered in Databases Mar 5

by Bharat Bhushan

80 views

2 votes

3 answers

15

#Self Doubt
A Relation R is in 3NF and have only 1 Candidate Key(may or may not be composite), then R is in BCNF. True or False??

Bharat Bhushan answered in Databases Mar 5

by Bharat Bhushan

225 views

2 votes

2 answers

16

ER Diagram: What is the cardinality of this relationship? is m-n cardinality correct? if not, why?
What is the cardinality of this relationship? is m-n cardinality correct? if not, why?

suvasish114 answered in Databases Mar 4

585 views

0 votes

0 answers

17

Ace workbook dbms

gaddalakonda_ganesh asked in Databases Feb 28

by gaddalakonda_ganesh

82 views

0 votes

2 answers

18

When is a group of attributes prime?
Given the candidate keys CD and DE and the functional dependency AB->CDE. Is CDE considered prime because all attributes (C, D and E) are prime? Or is it non-prime because CDE is not found in a candidate key as a whole? Therefore, my question is if a group of prime attributes is also prime due to its attributes or it has to be part of a candidate key as well.

chinmay_rajpurohit answered in Databases Feb 26

by chinmay_rajpurohit

182 views

1 vote

2 answers

19

GATE CSE 2023 | Question: 51
Consider the following table named $\text{Student}$ in a relational database. The primary key of this table is $\text{rollNum}.$ $\text{Student}$ ... database. SELECT * FROM Student WHERE gender = 'F' AND marks > 65; The number of rows returned by the query is ___________.

Hira Thakur answered in Databases Feb 16

898 views

1 vote

0 answers

20

GATE CSE 2023 | Question: 52
Consider a database of fixed-length records, stored as an ordered file. The database has $25,000$ records, with each record being $100$ bytes, of which the primary key occupies $15$ bytes. The data file is block-aligned in that each data ... required to identify the block in the data file that may contain a record with the key, in the worst case, is _____________.

admin asked in Databases Feb 15

by admin

1.8k views

0 votes

1 answer

21

GATE CSE 2023 | Memory Based Question: 34
Which one of the options given below refers to the degree (or arity) of a relation in relational database systems? Number of tuples stored in relation. Number of distinct domains of its relation schema. Number of attributes in relation. Number of entries in relation. closed

Hira Thakur answered in Databases Feb 6

421 views

0 votes

0 answers

22

TestBook TestSeries question to find max child possible in B+ Tree
In a B+ Tree index having order 6, which is the maximum number of child pointers it can have. Keys are numbered from 1 to 83. What can be the maximum number of nodes which can be used to store all the keys? A. 17 B. 19 C. 59 D. 57

Sahil_Lather asked in Databases Jan 29

by Sahil_Lather

111 views

0 votes

0 answers

23

Databases
Please explain option c.

Overflow04 asked in Databases Jan 25

76 views

0 votes

1 answer

24

CIL, UPPCL AE CS 2019
Consider the relation schemas R(A, B, C, D) and S(D, E, F). What will be the degree of the resultant schema R * S, where star (*) symbol represents the natural join operation? (A) 3 (B) 4 (C) 6 (D) 5

mohit jain answered in Databases Jan 24

76 views

0 votes

1 answer

25

TNPSC 2017
the materialization approach of query evaluation includes (from root to leaf) : (a) π, ∞, σ (b) π, σ, ∞ (c) σ, π, ∞ (d) σ, ∞, π

mohit jain answered in Databases Jan 24

72 views

0 votes

1 answer

26

CIL Part B
Consider the following relation schema R and S along with their tuple sets. R(A, B) = { <a1, b1 >, <a2, b1>, <a3, b1>, <a4, b1>, <a1, b2>, <a3, b2>, <a2, b3>, <a3, b3>, <a4, b3>, <a1, b4>, <a2, b4>, <a3, b4> } S(A) = ... operation? A. T(B) = {b1, b2, b4} B. T(B) = {b1, b3, b4} C. T(B) = {b1, b4) D. T(B) = {b1, b3}

mohit jain answered in Databases Jan 24

80 views

2 votes

1 answer

27

MadeEasy Test Series: Databases - Er Diagram
Identify total number of attributes in minimized relation ?

mohit jain answered in Databases Jan 20

496 views

2 votes

3 answers

28

MadeEasy Subject Test: Databases - Er Diagram

mohit jain answered in Databases Jan 20

240 views

1 vote

2 answers

29

MadeEasy Workbook: Databases - Er Diagram
The minimum number of tables needed to represent M,N,P,R1,R2 is … The given ans is 2. I think the ans should be 3.

mohit jain answered in Databases Jan 20

739 views

1 vote

1 answer

30

Ace Test Series: Databases - Er Diagram

mohit jain answered in Databases Jan 20

253 views

0 votes

0 answers

31

SQL | Not Exist

abhinowKatore asked in Databases Jan 17

by abhinowKatore

57 views

0 votes

0 answers

32

SQL
consider following relation How many number of records resulted by following SQL query? Select $T_{1}.A$ From R Where Exists (Select Count (*) From S Where R .C<S.F and S. E > 10 ); A 3 B 2 C 1 D 0

someshawasthi asked in Databases Jan 17

by someshawasthi

64 views

0 votes

2 answers

33

Made Easy Test Series | 3NF | True/False
A relation is in 3NF if every non-prime attribute of R is fully functionally reliant on every key of R TRUE FALSE

Souvik33 asked in Databases Jan 14

138 views

0 votes

1 answer

34

SQL Query
Write SQL command to find DepartmentID, EmployeeName from Employee table whose average salary is above 20000.

rayhanrjt asked in Databases Jan 6

132 views

0 votes

1 answer

35

Lock Compatibility in GATE IT 2007 | Question: 66
With reference to the GATE IT 2007 | Question : 66 In the following article from GeeksForGeeks : Lock Compatibility Diagram It can be clearly seen that if a transaction Ti owns a Shared lock on A, then a transaction Tj cannot take an Exclusive lock on ... (A) call in T2 will wait for T1, and T1 will wait for Lock_X(B) from T2, so hence a deadlock ?

ParthPratim asked in Databases Jan 6

87 views

0 votes

0 answers

36

Entity-relationship and Relational Model:el:Convert the following entity-relationship diagram into tables of relational model

Usama2112 asked in Databases Jan 1

94 views

0 votes

1 answer

37

starvation in strict timestamping
Is starvation possible in strict timestamping?

Tara33 asked in Databases Dec 27, 2022

by Tara33

66 views

0 votes

1 answer

38

Casecading rollback in WD and WW
Is the possibility of cascading rollbacks more in Wound and Wait or in Wait Die?

Tara33 asked in Databases Dec 26, 2022

by Tara33

97 views

0 votes

0 answers

39

Unacademy AIMT -1
the answer is 28

TusharKumar asked in Databases Dec 23, 2022

209 views

2 votes

1 answer

40

Who manages what? (ACID peoperties)
Which manager manages each of the ACID properties? I found that transaction processing (TP) manager manages Isolation from wikipedia, meanwhile I read from another source that it is managed by concurrency control manager. Also what about the other ... which managers control them? Can you please list down the managers of the properties or any sources know to you?

h4kr asked in Databases Dec 19, 2022

by h4kr

128 views

To see more, click for all the questions in this category.

Recent questions and answers in Databases