Recent questions in Databases

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1

Er diagram minimum table
Is this a correct way to find the minimum number of tables in a ER DIAGRAM?

asked Jun 10 in Databases by kshitij (79 points) | 24 views

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2

DBMS: SELF DOUBT .
Is basic 2 phase locking always recoverable?

asked Jun 10 in Databases by Hirak Active (3k points) | 21 views

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3

ER Model Self Doubt
How to represent referential integrity constraint in ER model? pls explain with diagram

asked Jun 7 in Databases by aditi19 Active (3.7k points) | 60 views

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4

ACE Test series: Database

asked Jun 7 in Databases by ushamya (457 points) | 50 views

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5

B TRees DBMS Self doubt
In case of B Trees we split a node on insertion in case of overflow, is there any possible case in which this may lead to underflow also? as a key is promoted to parent the children formed may have subtrees, which may be broken such that we get underflow somewhere? just a thought

asked Jun 7 in Databases by manisha11 Active (2k points) | 22 views

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6

ACE Test Series : dependency preserving
R(A,B,C) is a relation.Which of the following don't have dependency preserving BCNF decomposition? A->B, B->C A->B,B->C,C->A AB->C,C->A None of these

asked Jun 3 in Databases by ushamya (457 points) | 51 views

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7

Virtual GATE Test Series ER to Relational Model
how many tables are required?

asked May 28 in Databases by aditi19 Active (3.7k points) | 120 views

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8

Virtual Gate Test Series Database
A' is set of all possible schedules 'C' is set of all possible schedules that are guaranteed to produce a correct final result 'S' is the set of all serializable schedules 'P' is the set of all schedules possible under 2-phase locking protocol Which is FALSE? $P\subseteq C$ $S\subset P$ $S\subseteq P$ $P\subset C$

asked May 28 in Databases by aditi19 Active (3.7k points) | 94 views

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9

Doubt on database normalization for relation having all prime attributes
In a relation, if every attribute is prime but key may not be simple then the relation is in ______. A. 1NF B. 2NF C. 3NF D. BCNF

asked May 27 in Databases by Tuhin Dutta Loyal (9k points) | 94 views

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10

MADE EASY Relational Algebra
In a relational algebra ∩ is not a basic operator, to make it basic only relational operator we should have are X, – X, U U, –

asked May 25 in Databases by Hirak Active (3k points) | 38 views

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11

VANI Question Bank :DBMS
Minimum number of tables required to represent the relation R where the $A_n$ stands for the primary key of each entity is ___________

asked May 25 in Databases by Hirak Active (3k points) | 46 views

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12

#DBMS_ER Model
A university database contains information about professors (identified by SSN) and courses (identified by courseid). Professors teach courses; each of the following situations concerns the Teaches relationship set. For below situation, draw the ER diagram: ... in a team can teach the course. Model this situation introducing additional entity sets and relationship sets if necessary.

asked May 24 in Databases by Sumiran Agrawal (85 points) | 33 views

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13

Geeksforgeeks: GATE CS Mock 2018
Consider the given schedule and choose the suitable option S = T1:R(x), T1:R(y), T1:W(x), T2:R(y), T3:W(y), T1:W(x), T2:R(y) Schedule is view serializable Schedule is conflict serializable but not view serializable Schedule is view serializable but not conflict serializable Neither view serializable nor conflict serializable

asked May 22 in Databases by ushamya (457 points) | 29 views

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14

UGC NET 2015 DEC-III
Consider the following three SQL queries (Assume the data in the people table): (a)Select Name from people where Age > 21; (b)Select Name from people where Height > 180; (c)Select Name from people where (Age > 21) or (Height > 180); If ... 10 rows and 7 rows in the result set respectively, then what is one possible number of rows returned by the SQL query (c) ?

asked May 22 in Databases by aditi19 Active (3.7k points) | 33 views

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15

Made Easy Test Series:Databases-Tables
Number of tables required in above ER diagram will be _____________ Is $R_{1}$ create separate table or not?? and $R_{2}$ look like if we remove loop from it?? Answer given for table $E_{1}R_{1}$ Key will be $AC$ , with ... Entities. So, it will add one extra table. I already read https://gateoverflow.in/229580/madeeasy-test-series-number-of-tables-required

asked May 22 in Databases by srestha Veteran (111k points) | 53 views

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16

Made Easy Test Series: Database-Normalization
Consider the relation $R\left ( A,B,C,D,E \right )$ with functional dependencies $F=${ $A\rightarrow B$ $BC\rightarrow E$ $ED\rightarrow A$ } Number of additional relation required to convert it into lossless , dependency preserving $3NF$ decomposition is _____________ What is meaning of additional relation (Here no table mentioned previously)??

asked May 19 in Databases by srestha Veteran (111k points) | 69 views

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17

IIIT-H INTERVIEW
Why does OS and DBMS have their own synchronisation mechanisms, when OS can alone do it and it sits at the bottom of DB?

asked May 18 in Databases by shraddha priya Active (3.6k points) | 106 views

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2 answers

18

Raghuramkrishnan 3e Exercise 5.1 Question no-5 page no-175 SQL
Class(name, meets_at, room, fid) Faculty(fid, fname, deptid) Find the names of faculty members who teach in every room in which some class is taught

asked May 18 in Databases by aditi19 Active (3.7k points) | 65 views

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19

Made Easy Test Series:Database-Indexing
The minimum number of nodes (both leaf and non-leaf) of $B^{+}$ tree index required for storing $5500$ keys and order of $B^{+}$ tree is $8$________________(order is max pointers a node can have) See here first level should be divide by $7$ ... pointer of 1st level has $8$ pointer in 2nd level. Am I missing something?? But in ans they divided by only $8$ :(

asked May 17 in Databases by srestha Veteran (111k points) | 52 views

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20

Made Easy Test Series:Database-SQL
Find the name of Sailors with a higher rating than all sailors with age $<22?$ $Query1: $ Select S.name from sailor S where not exists (Select * from sailor $S_{2} $where $S_{2}.age<22$ and $S.rating<=S_{2}.rating$ ... above query?? I think Query2 and Query3 itself differentiate with ANY and ALL keyword. But what about Query1? Will it return ALL tuples?

asked May 14 in Databases by srestha Veteran (111k points) | 97 views

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21

Made Easy Test Series:Databases-Indexing
Consider the following statement below: $A)$ A clustered index may be either sparse or dense. $B)$ Every $B^{+}$ tree index is dense. Which of the above statement is true? Is clustering Index can be dense. Dense means non-ordering field, but clustering field should be ordering field right??

asked May 13 in Databases by srestha Veteran (111k points) | 50 views

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22

ISI2018-PCB-B10
Consider two $n \times 1$ vectors $u$ and $v$ , stored as table $U(ind,val)$ and $V(ind,val)$ with the same schema A row $(i,u_i)$ of table $U$ specifies the $i^{th}$ element of vector $u$ has value $u_i$ (similarly for $v$, respectively). ... $u + v$ of the two vectors $u$ and $v$. Explain your solution.

asked May 12 in Databases by akash.dinkar12 Boss (40.4k points) | 17 views

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23

dbms normalization - 2nf/bcnf query
Consider the following relational schemes: R(A, B, C, D, E, F) and S(A, B, C) with in the following functional dependencies: I. AB --> C II. C --> ABDE III. ADE --> F Assume {A,B} is the key for both schemes. Which of the ... C is the relation for the S table, which satisfies BCNF properties. (So S is in BCNF) Please let me know if it is correct or not.

asked May 10 in Databases by pritam946 (9 points) | 33 views

+1 vote

1 answer

24

Made Easy Test Series:Database-Super-Keys
Consider the relation $R\left ( A,B,C,D,E \right )$ $A\rightarrow BC$ $C\rightarrow E$ $B\rightarrow D$ $E\rightarrow A$ Total number of superkeys present in relation will be ____________________

asked May 9 in Databases by srestha Veteran (111k points) | 57 views

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25

Made Easy Test Series:Relational Algebra
... this implication holds true?? Selection operation is commutative. But is two project operation can be merge in one project operation? Can project operation removes duplicates too??

asked May 9 in Databases by srestha Veteran (111k points) | 30 views

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26

Any good resource for developing concepts on transactions in SQL?

asked May 9 in Databases by aditi19 Active (3.7k points) | 11 views

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27

Molina Exercise-6.3.1 Question no-f Page no-280 SQL
Product(maker, model, type) PC(model, speed, ram, hd, price) Laptop(model, speed, ram, hd, screen, price) Printer(model, color, type, price) Find the maker(s) of the PC(s) with the fastest processor among all those PC 's that have the ... p where p.speed IN( select max(p1.speed) from PC p1 where p1.ram IN( select MIN(p2.ram) from PC p2)))

asked May 8 in Databases by aditi19 Active (3.7k points) | 16 views

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28

Natural Join Self Doubt
how to write the query for natural join on three relations in SQL using the NATURAL JOIN clause?

asked May 8 in Databases by aditi19 Active (3.7k points) | 34 views

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29

Raghuramkrishnan Exercise-4.3 question 11 page no-127 Relational Algebra
Suppliers(sid, sname, address) Parts(pid, pname, color) Catalog(sid, pid, cost) Find the pids of the most expensive parts supplied by suppliers named Yosemite Sham

asked May 8 in Databases by aditi19 Active (3.7k points) | 19 views

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30

Raghuramkrishnan Exercise-4.3 page-127
Given relation catalog(sid, pid, cost) Find pairs of sids such that the supplier with the first sid charges more for some part than the supplier with the second sid what is the relational algebra expression for this?

asked May 7 in Databases by aditi19 Active (3.7k points) | 16 views

tags	tag:apple
author	user:martin
title	title:apple
content	content:apple
exclude	-tag:apple
force match	+apple
views	views:100
score	score:10
answers	answers:2
is accepted	isaccepted:true
is closed	isclosed:true

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