Recent questions tagged databases - GATE CSE Doubts

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Previous Gate
https://gateoverflow.in/2510/gate1994-14 For a B+ - tree of order d with n leaf nodes, the number of nodes accessed during a search is O(−) Please explain me Sachin’s answer in extra details. I cant even understand after 2 lines.

asked Sep 11 in Databases by Gupta731 (17 points) | 13 views

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Made Easy Subject Wise DBMS
Consider the following schedule: S: r1(A), r2(A), r3(A), r4(A), w1(B), w2(B), w3(B), w4(B). Find the number of all possible view-equivalent schedules. Find the number of all possible conflict-equivalent schedules. How many serializable schedules are there that are not conflict serializable.

asked Sep 10 in Databases by Ollie (453 points) | 63 views

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Self Doubt Database recoverability
All conflict serializable schedules are recoverable.[True or False] Please provide the explanation as well as reference too if possible

asked Sep 10 in Databases by Ollie (453 points) | 35 views

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Made Easy Subject Wise Database
If a relation is in BCNF surely it will be in a 4NF as well. [True or False, with explanation] Made Easy Solution : True. [I think False]

asked Sep 9 in Databases by Ollie (453 points) | 32 views

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Made Easy DBMS
Which of the following statement is false? Relation with every attribute is prime, always in BCNF. Relation with every attribute prime always in 3NF. Relation R which satisfies 3NF and atmost one compound candidate key is also in BCNF Relation with every candidate key is ... , so as per me, Option (D) also is false, while according to Made Easy it is true, someone please clarify.

asked Sep 9 in Databases by Ollie (453 points) | 21 views

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Self Doubt on Transcation & Concurrency Control
Why this schedule is not View Serializable?? Anyone please elaborate this.

asked Sep 7 in Databases by AbhayPrajapati (7 points) | 29 views

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#self doubt #databases #normqlisation
If we decompose R(ABCDE) into 2nd normal form what all tables we get . Given FDs(A->C,C->D,D->E,C->A).

asked Sep 4 in Databases by Anujjain (7 points) | 36 views

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applied test series
The original answer says that every team participating should have exactly one refree which I think is wrong. my observations:- 1. if there is a refree then he/she needs to instruct atleast a single game 2.if there is a match btw two teams then they ... teams present that doesn't plays a match. PS-here the refree entity is in total participation please correct me if I am wrong

asked Sep 4 in Databases by Sahil91 (5 points) | 9 views

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Self Doubt - (PYQs)
https://gateoverflow.in/1485/gate1999-2-7-ugcnet-june2014-iii-25 In this question if $R_1 \cap R_2 = \phi$ then will the decomposition will be lossy but does that mean that $R_1$ and $R_2$ individually can’t be in 2NF, 3NF or BCNF?

asked Sep 2 in Databases by Mellophi (325 points) | 10 views

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Raghu Ramkrishnan - Transactions and Concurrency Control

asked Aug 30 in Databases by pritishc (23 points) | 43 views

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Made Easy Workbook
Please someone solve Q35.

asked Aug 28 in Databases by Mellophi (325 points) | 28 views

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ME TEST SERIES
Can anyone tell how this works?

asked Aug 27 in Databases by S.R. (433 points) | 24 views

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Self doubt DBMS Conflict Equivalent schedules
$\text{Consider the transactions given below}$ What are the number of conflict equivalent schedules possible What is the approach to solve such questions T1 T2 T3 $r_{A}$ $w_{B}$ $r_{A}$ $w_{B}$ $r_{A}$ $w_{B}$

asked Aug 26 in Databases by S.R. (433 points) | 36 views

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MADE EASY CN+DBMS TEST SERIES GATE 2020
I only II only Both None Which option is correct give justification

asked Aug 26 in Databases by S.R. (433 points) | 17 views

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Self Doubt (Nested Loop Join)
Can someone please clarify why we keep the smaller loop outer and the bigger loop inner? (i.e. why do we select the relation with smaller number of tuples as the outer relation)

asked Aug 16 in Databases by Mellophi (325 points) | 17 views

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#DBMS #Self-Dobt
What is the maximum number of candidate keys we can have?

asked Aug 15 in Databases by munishchaturvedi (19 points) | 19 views

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#DBMS #Self-Doubt
Can phi be a super Key? In what corner cases can it be? What is the maximum number of Super Keys?

asked Aug 15 in Databases by munishchaturvedi (19 points) | 26 views

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Self-Doubt Normalization
Is Every Table with 2 single valued attribute is in 2nf, 3nf, bcnf? Why?

asked Aug 14 in Databases by munishchaturvedi (19 points) | 29 views

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Self-Doubt #DBMS #Candidate Keys
If candidate keys given are A1, A2, A3, then waht are number of super keys if we only have those n attribues in relation A1 to A?.

asked Aug 14 in Databases by mamtuj (-25 points) | 31 views

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Self-Doubt #DBMS #Index
Can anyone tell me on which fields we can define Clustering Index on? What are conditions?

asked Aug 14 in Databases by mamtuj (-25 points) | 15 views

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#self doubt databases
Can we have more than one entries as NULL under a column which is a candidate key.Since Two entries can't be same under a candidate key column.so here Null values under candidate key will be treated as distinct or same.

asked Aug 11 in Databases by Anujjain (7 points) | 7 views

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#made-easy-test-series
Given the following relational schemas Student (studId, name, age, sex, deptNo, advisor) ,Department (deptId, DName, hod, phoneNo) Which of the following will be the TRC query to obtain the department names that do not have any girl students? 1.{d.Dname | department(d) ∧ ~ ((∃(s)) ... | department(d) ∧ ~ ((∃(s)) student(s) ∧ s.sex = F' ∧ s.deptNo = d.deptId)} 4.None of these

asked Aug 11 in Databases by 404 found (11 points) | 32 views

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#DBMS 2NF doubt
Consider a Relation R(ABCDEFG) with AB as key and a FD as below – DAE ------→ F Is this Relation R in 2NF?

asked Aug 10 in Databases by iarnav (67 points) | 15 views

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What is the highest normal form of the relation?
Given relation R(a,b,c,d,e,f,g). Functional dependencies are as follows:- { a → b,d,e,g c,d → f f → c e,g → d } What is the highest normal form?

asked Aug 8 in Databases by sdutta (5 points) | 18 views

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#DBMS #Normalization State True/False for 3NF.
Statement: A non prime attribute can be transitively dependent on a key in a 3NF relation. Is it True/False. please explain it with a reason.

asked Aug 5 in Databases by iarnav (67 points) | 24 views

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self-doubt 2-phase locking
Is this schedule following 2-phase locking? how is serializability achieved here?

asked Aug 5 in Databases by Akshay Nair (5 points) | 16 views

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Serializability
Are all serializable schedules recoverable, cascade-less, strict???

asked Aug 4 in Databases by manas_kulkarni (1 point) | 29 views

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DBMS transactions
Are all serializable schedules recoverable, cascade-less, strict???

asked Aug 3 in Databases by manas_kulkarni (1 point) | 17 views

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Objective Practice Sets Made Easy
The answer given is C but I don’t understand. I think B has partial dependency because attribute set X which has some attributes from the key set determines the attribute set A.

asked Jul 30 in Databases by abhi97.dutta (5 points) | 8 views

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Made Easy Test series 2020
Is it Serializable schedule? Please give full explaination , if any

asked Jul 10 in Databases by prajjwalsingh_11 (13 points) | 18 views

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Conflict Equivalence-Databases (Self doubt)
consider statement 1 : Two schedules are conflict equivalent when the precedence graphs are isomorphic. Is this statement correct or wrong. It is the counter example for the same S1: = R1(A) R2(A)W1(A) W2(A) S2: = R1(A) ... present in both schedules ( say T1 and T2) must be same.Is this also the condition for checking Conflict Equivalency check?

asked Jul 9 in Databases by prajjwalsingh_11 (13 points) | 6 views

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Madeeasy dbms workbook 2020 , chapter : relation algebra ,tuple relational calculus and sql, question number 15

asked Jul 4 in Databases by swatiChaudhary (11 points) | 41 views

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deadlock in databases
my question is isn’t wait wound and wait die deadlock prevention algo so how can we say that they are deadlock avoidance and how they can cause more aborts than needed?

asked Jun 25 in Databases by abcd9982 (81 points) | 10 views

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Normalization Self doubt
R = {Student ID, Last Name, First Name, Course ID, Course Section, Course Name, Grade, Professor Last Name, Professor First Name, Bldg, Office #, Semester} with following functional dependencies FD1 = Student ID --> Last Name, First Name FD2 ... , Prof_FName, Bldg, Office# CONVERTING IT TO 2NF IM GETTING THREE TABLES BUT ANSWER IS GIVEN AS 4 TABLES. PLEASE HELP ME.

asked Jun 24 in Databases by Sowmya tatavarthi (5 points) | 9 views

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transactions
a) S with no dirty read then S is cascadeless rollback but may not be strict recoverable b) S with no dirty read then S is recoverable but may not be cascadeless rollback c) S with no dirty read then S is conflict serializable schedule d) S with no dirty read then S is strict recoverable

asked Jun 24 in Databases by abcd9982 (81 points) | 77 views

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made_easy_test_series

asked Jun 24 in Databases by abcd9982 (81 points) | 17 views

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Relational table

asked Jun 18 in Databases by Tris Ravi (5 points) | 12 views

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Extended Entity Relationship Diagram
In a country, institutions are hiring employees for the position of either a junior scientist, senior scientist, or a lab assistant. We want to store the following data: 1. For each employee: First name, Date of Birth, position. 2. ... should not have redundant entity sets, attributes etc. If you need to make any assumptions, explain them in your answer.

asked Jun 18 in Databases by Tris Ravi (5 points) | 7 views

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NIELIT- B/B+ tree
Identify the true statement from the given statements: Number of child pointers in a B/B+ tree node is always equal to number of keys in it plus one B/B+ tree is defined by a term minimum degree. And minimum degree depends on hard disk block size, key and address size (1) (1) and (2) (2) None of these

asked Jun 8 in Databases by Rishav Kumar Singh (5 points) | 12 views

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Self Doubt Database

asked Jun 7 in Databases by Abhipsa (5 points) | 11 views

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