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1

SELF DOUBT
T(1) T(2) R(A) W(A) W(A) SUPPOSE WE HAVE TWO TRANSACTION T1 AND T2. AND ALSO INTIAL VALUE OF A IS 100. THEN WE FIRST READ A AND THEN FROM T(2) WRITE A . SO MY DOUBT IS WHEN I AM WRITING A WITHOUT ANY CONDITION SPECIFYING . WHAT DOES IT MEAN ???? WHETHER A IS GOING TO CHANGE TO ANY VALUE AND WE DONT CONDITION OR IT IS JUST WRITING A VALUE WHICH IS 100. I AM NOT GETTING THIS CONCEPT .

asked 13 hours ago in Databases by Deepanshu Junior (619 points) | 21 views

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1 answer

2

Er model
why we can merge one-one relation in two table despite of partial participation at both end.it is possible of inserting too many null value?

asked 15 hours ago in Databases by shubhgol (17 points) | 26 views

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1 answer

3

Recoverable cascading lost update and strict

asked 1 day ago in Databases by Deepalitrapti (195 points) | 79 views

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4

gate 2009
What does this relational calculus evaluates to? (A) Names of employees with a male supervisor. (B) Names of employees with no immediate male subordinates. (C) Names of employees with no immediate female subordinates. (D) Names of employees with a female supervisor. Can you please explain how to deal with the negation?

asked 1 day ago in Databases by vk_9_1_9 (29 points) | 12 views

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5

#Test series
Let R(A, B, C, D, E) be a relation which has 500000 records. Size of each record is 200 B. Size of attribute A is 16 B. Size of pointer is 4 B and size of the block is 2400 B (assume elements are stored in sorted order of ... difference of the cost in term of number of block transfer from the disk when multilevel index used and when binary search applied without indexing is _______.

asked 1 day ago in Databases by himgta Active (1.1k points) | 13 views

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2 answers

6

ER To RDBMS
Consider an Entity-Relationship (ER) model in which entity sets E1 and E2 are connected by an 1:1 relationship R. Primary key of E1 and E2 are A and B respectively. There is total participation at one end (say E1). Find minimum number Of table required in RDBMS

asked 1 day ago in Databases by sunnyzohan (7 points) | 18 views

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1 answer

7

Verifying Relational Algebra Question
I think it should be option a) All query $1,3,4$ are equivalent but $2$ is not equivalent. Query $2$ should be $\prod \text{Room no,hotel no,type,price}(\sigma \text{type='single' } \wedge \text{price=200 })$

asked 1 day ago in Databases by Anand. Active (2.1k points) | 21 views

+1 vote

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8

Equi_Joins
https://gateoverflow.in/1670/gate1998-1-33 What will be the attributes of resultant table : (A B) or (C D) ?

asked 1 day ago in Databases by daksirp (213 points) | 30 views

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1 answer

9

MADE EASY TEST SERIES
What will be the minimal cover of given FD's?

asked 2 days ago in Databases by amitqy (35 points) | 24 views

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1 answer

10

File structure

asked 2 days ago in Databases by Deepalitrapti (195 points) | 26 views

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11

Foreign key
Foreign key can not be used to refers to its own relation????

asked 2 days ago in Databases by Deepalitrapti (195 points) | 20 views

+1 vote

1 answer

12

SQL_IN_Query
Answer should be $0$ row,right?

asked 2 days ago in Databases by Anand. Active (2.1k points) | 71 views

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13

Foreign key

asked 2 days ago in Databases by Deepalitrapti (195 points) | 30 views

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14

self doubt
https://gateoverflow.in/3641/gate2006-it-85 IN THE SOLUTION BY ARJUN SIR THERE ARE STATEMENTS LIKE Supposing our earlier selection is <102,104> then this requires 3+7*2=17comparisons. If the order was <104, 102>, then 2+8*2=18comparisons. SO WHAT IS 3 IN 3 +7*2=17 HERE I AM NOT GETTING THAT

asked 2 days ago in Databases by Deepanshu Junior (619 points) | 24 views

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15

E r model
[closed]

asked 2 days ago in Databases by Deepalitrapti (195 points) | 33 views

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16

DBMS indexing
Why unspanned organization is preferrable for fixed length record ??

asked 3 days ago in Databases by Nitesh Choudhary Active (2.6k points) | 19 views

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17

self doubt
https://gateoverflow.in/1846/gate2006-68 I AM NOT GETTING THIS QUESTION CONCEPTS

asked 3 days ago in Databases by Deepanshu Junior (619 points) | 33 views

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2 answers

18

Natural Joins
Please clear my doubt by solving this !!

asked 3 days ago in Databases by daksirp (213 points) | 25 views

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0 answers

19

Sparse dense

asked 3 days ago in Databases by Deepalitrapti (195 points) | 14 views

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0 answers

20

Primary idex secondary index

asked 3 days ago in Databases by Deepalitrapti (195 points) | 14 views

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1 answer

21

Made easy test series
Why option d is incorrect?

asked 4 days ago in Databases by Avik Chowdhury Junior (737 points) | 36 views

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1 answer

22

Sparse index and dense index

asked 4 days ago in Databases by Deepalitrapti (195 points) | 43 views

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0 answers

23

self doubt
just random query so my question is that I write WHERE e.deptno = d.deptno . OKK SO IF I WRITE INSTEAD OF THIS d.deptno.=e.deptno. THEN CAN IT EVALUATE SAME VALUE OR DIFFERENT? AS IN SOME BIG QUESTIONS I AM DOING THIS WRONG SO HELPPP SELECT e.ename, d.dname FROM emp e, dept d WHERE e.deptno = d.deptno AND e.sal > 1000;

asked 4 days ago in Databases by Deepanshu Junior (619 points) | 7 views

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24

Gate 04 , DBMS ,FILE STRUCTURE,B TREES
https://gateoverflow.in/?qa=blob&qa_blobid=2550937292644146307 Plz explain, if we are asked to put each b tree node to fit in one block then why don't we consider it a leaf node , why do we need to consider block pointers .

asked 5 days ago in Databases by Shashi Shekhar 1 (87 points) | 10 views

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1 answer

25

Bulk loading

asked 5 days ago in Databases by Deepalitrapti (195 points) | 20 views

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0 answers

26

DOUBT
IN SQL WHILE WE USING UNIQUE CONSTRAINT , ARE WE ALLOWED TO USE NULL VALUE OR NULL VALUES OR NONE OF THEM ????????

asked 5 days ago in Databases by Deepanshu Junior (619 points) | 36 views

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1 answer

27

B tree B+ tree

asked 5 days ago in Databases by Deepalitrapti (195 points) | 25 views

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2 answers

28

ER Model

asked 6 days ago in Databases by Rishabh Baghel (39 points) | 54 views

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0 answers

29

SELF DOUBT GATE2009-56
I AM NOT GETTING THIS QUESTION CONCEPT . PLEASE HELP Consider the following relational schema: Suppliers(sid:integer−−−−−−−−, sname:string, city:string, street:string) Parts(pid:integer−−−−−−−−−, pname:string, color:string) Catalog(sid:integer, pid:integer−−−−−−−−−−−−−−−−−−,cost:real) ... is in 3NF but not in BCNF The schema is in 2NF but not in 3NF The schema is not in 2NF

asked Aug 11 in Databases by Deepanshu Junior (619 points) | 19 views

0 votes

1 answer

30

#Made_Easy_Workbook
T1:R1(A)R1(B)W1(B) T1:R2(A)R2(B)W2(B) (a)number of serializable schedule. (b) number of non-serializable schedule. (c) number of non serial schedules which are serializable.

asked Aug 11 in Databases by Anil Ji Active (3.3k points) | 26 views

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views	views:100
score	score:10
answers	answers:2
is accepted	isaccepted:true
is closed	isclosed:true

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