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ER‐model. Relational model:Relational algebra, Tuple calculus, SQL. Integrity constraints, Normal forms. File organization, Indexing (e.g., B and B+ trees). Transactions and concurrency control.

$$\small{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count}&2&2&2&2&3&2&2&2.2&3
\\\hline\textbf{2 Marks Count}&3&2&3&3&1&2&1&2.3&3
\\\hline\textbf{Total Marks}&8&6&8&8&5&6&\bf{6}&\bf{6.8}&\bf{8}\\\hline
\end{array}}}$$

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NTA NET DEC 2019 (SQL_Query)
Given two tables EMPLOYEE (EID,ENAME,DEPTNO) DEPARTMENT(DEPTNO ,DEPTNAME) Find the most appropriate statement of the given query Select count(*) total from employee where DEPTNO IN (D1 ,D2) group by DEPTNO having count(*)>5 1)Total number of ... )Display total number of employees in both department D1 and D2 4)The output of the query must have at least two rows

asked Dec 20, 2019 in Databases by Sanjay Sharma Boss (49.3k points) | 81 views

+1 vote

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

asked Jun 10, 2019 in Databases by kshitij (295 points) | 90 views

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

asked Jun 10, 2019 in Databases by Hirak Active (3.6k points) | 86 views

+1 vote

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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, 2019 in Databases by manisha11 Active (2.3k points) | 66 views

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Virtual Gate Test Series: Databases - Schedules
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, 2019 in Databases by aditi19 Active (5.2k points) | 133 views

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#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, 2019 in Databases by Sumiran Agrawal (101 points) | 94 views

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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, 2019 in Databases by aditi19 Active (5.2k points) | 113 views

+1 vote

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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, 2019 in Databases by srestha Veteran (119k points) | 106 views

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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, 2019 in Databases by shraddha priya Active (4k points) | 157 views

+1 vote

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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, 2019 in Databases by srestha Veteran (119k points) | 124 views

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ISI2018-PCB-CS10
Consider two $n \times 1$ vectors $u$ and $v$ , stored as table $U(\text{ind,val})$ and $V(\text{ind,val})$ with the same schema A row $(i,u_i)$ of table $U$ specifies the $i^{th}$ element of vector $u$ has value $u_i$ ... $u + v$ of the two vectors $u$ and $v$. Explain your solution.

asked May 12, 2019 in Databases by akash.dinkar12 Boss (42.4k points) | 87 views

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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, 2019 in Databases by srestha Veteran (119k points) | 127 views

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Any good resource for developing concepts on transactions in SQL?

asked May 9, 2019 in Databases by aditi19 Active (5.2k points) | 55 views

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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, 2019 in Databases by aditi19 Active (5.2k points) | 45 views

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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, 2019 in Databases by aditi19 Active (5.2k points) | 70 views

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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, 2019 in Databases by aditi19 Active (5.2k points) | 77 views

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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, 2019 in Databases by aditi19 Active (5.2k points) | 58 views

+1 vote

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Made Easy Databases
Consider the following schedules with data item x The number of serial schedules which are view equal to schedules but not conflict equal is ___________.

asked May 5, 2019 in Databases by Hirak Active (3.6k points) | 90 views

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MADE EASY FREE TEST Q47
Find the total number of tables required. Ans given was 4, bit how can it be 4? According to me, E1 and E2 will require 2 tables at begining, then for E3 and E1 we need another table, then for E2 and E3 we need another and for E3 and E2’s many to many relation i need another one. So total =5. But ans given was 4.. explain pls.

asked May 4, 2019 in Databases by Hirak Active (3.6k points) | 32 views

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Self Doubt on SQL AND operator
Here why does the 5th query select * from employees natural join works_on where PID = 'X' AND PID='Y'; is not working The queries are The output are

asked Apr 30, 2019 in Databases by kd..... Junior (853 points) | 95 views

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Self Doubt: Databases ER diagram
Here if check_txn contains its own attributes then during converting into a relational model where does its attributes will be placed either in account side ( strong entity set) or check side (weak entity set)? and why?

asked Apr 26, 2019 in Databases by kd..... Junior (853 points) | 52 views

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ISI DBMS
Consider the relations r1(A, B, C), r2(C, D, E) and r3(E, F). Assume that the set of all attributes constitutes the primary keys of these relations, rather than the individual ones. Let V (C, r1) be 500, V (C, r2) be 1000, V (E, r2) be ... r2 has 1500 tuples, and r3 has 750 tuples, then give the ordering of the natural join r1 ▷◁ r2 ▷◁ r3 for its efficient computation. Justify your answer

asked Apr 18, 2019 in Databases by Priyanka17 Active (1.7k points) | 49 views

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#DBMS#Transaction

asked Apr 17, 2019 in Databases by Golam Murtuza (421 points) | 22 views

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Doubt on a gate question
https://gateoverflow.in/968/gate2003-85 How in the above question the functional dependency (date of birth -> age) is a partial functional dependency. (As told in the selected answer for this question) Because according to navathe the definition of partial functional dependency ... X and the dependency still holds; that is, for some A belongs to X (X - {A}) -> Y.

asked Apr 13, 2019 in Databases by Kushagra Chatterjee Loyal (9.8k points) | 55 views

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#SELF DOUBT(WEAK ENTITY IN DBMS)
Can a weak entity depend on more than one strong entity?If yes then how does that exaclty work?

asked Apr 8, 2019 in Databases by codingo1234 Junior (933 points) | 33 views

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ISI2017-PCB-CS-3-b
Consider the following relations: $\text{STD_CHOICES } (\underline{\text{Student_ID}}, \underline{\text{Course_ID}}, \text{Semester})$ and $\text{COURSE_ASSIGN} (\underline{\text{Teacher_ID}}, \underline{\text{Course_ID}}, \underline{\text{Semester}})$. The ... the ID for all the students who have not been taught by the same teacher in more than one course across all semesters.

asked Apr 8, 2019 in Databases by akash.dinkar12 Boss (42.4k points) | 62 views

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self doubt
In this Question , it is said that S is serializable .. so if S is conflict serializable then the precedence graph will be acyclic and we can use Topological sort to get a serial schedule, but what if the graph is not conflict serializable and is view serializable, ... use topological sort to get a serial schedule .. then how come the answer is (A). Topological sort .. Please Help!!

asked Apr 5, 2019 in Databases by _Bash_ (63 points) | 19 views

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#self doubt
my doubt is- when question is said find minimum no.of table to given E-R diagram,and additional condition table are satisfying 1NF/2NF/3NF. how we conclude table is 1NF/2NF/3NF.

asked Apr 5, 2019 in Databases by sandeep singh gaur (307 points) | 18 views

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self doubt
What is the correct answer of this Question and what are the Minimized tables ???

asked Apr 4, 2019 in Databases by _Bash_ (63 points) | 60 views

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DBMS Korth Edition 4 Exercise 16 Question 31 (Page No. 636)
Give example schedules to show that if any of lookup, insert or delete do not lock the next key value, the phantom phenomenon could go undetected.

asked Apr 3, 2019 in Databases by akash.dinkar12 Boss (42.4k points) | 33 views

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author	user:martin
title	title:apple
content	content:apple
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force match	+apple
views	views:100
score	score:10
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