Recent questions tagged relational-calculus

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RaghuramKrishnan
relation parts(pid, pname, color) catalog(sid, pid, cost) find the sids of suppliers who supply every red part. can someone give the TRC and DRC expression for this?

asked Nov 26 in Databases by aditi19 Active (2.1k points) | 14 views

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Korth
give domain relation calculus expression works(person-name, company-name, salary) find the names of all employees who earn more than every employee of Small Bank Corporation

asked Nov 4 in Databases by aditi19 Active (2.1k points) | 22 views

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3

Relational Algebra
Online Site For practicing Relational Algebra https://dbis-uibk.github.io/relax/calc.htm

asked Oct 28 in Databases by kumar.dilip Active (3.1k points) | 61 views

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4

doubt
How we find the given calculus is safe or not

asked Sep 8 in Databases by bhavnakumrawat5 (193 points) | 32 views

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1 answer

5

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 Aug 17 in Databases by Anand. Active (2.2k points) | 100 views

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1 answer

6

Tuple Relational Calculus Query - Confirm the Answer

asked Jul 2 in Databases by Harsh Kumar Junior (893 points) | 98 views

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1 answer

7

Tuple relational calculus - Seeking advice

asked Jul 1 in Databases by Harsh Kumar Junior (893 points) | 73 views

+1 vote

2 answers

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Tuple Relational Calculus - What is the difference between these two types of bounded variables in the expressions?

asked Apr 15 in Databases by tarunmaganti (275 points) | 98 views

+3 votes

1 answer

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GATE1993-24
The following relations are used to store data about students, courses, enrollment of students in courses and teachers of courses. Attributes for primary key in each relation are marked by *'. Students (rollno*, sname, saddr) courses (cno*, cname) enroll(rollno*, cno*, ... ? If yes, prove that it is in 3 NF. If not normalize, the relations so that they are in 3NF (without proving)?

asked Feb 5 in Databases by jothee Veteran (112k points) | 277 views

+2 votes

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Relational algebra
I have two doubts: 1) A natural join B What will be the result when B don't have any tuple in it. Like in B their is relational algebra expression which is selecting Cars of green color but their is no green color car in table. What will be the ... B In above divison if B is a relational algebra expression returning nothing ( like the B in case 1). What will be the result ?

asked Jan 14 in Programming by ♥_Less Active (1k points) | 100 views

+1 vote

2 answers

11

Test Series
Let r and s be two relations over the relational schemas R and S respectively, and let A be an attribute in R. Then the relation algebra expression σ(A=a) (r⋈s) is always equal to( Marks: -0.33 ) σ(A=a) (r)⋈s r None of the above σ(A=a) (r)

asked Jan 2 in Databases by ankit_thawal Active (2.1k points) | 91 views

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12

Tuple relational calculus
What does the following tuple relational calculus query produce? • Student (Student_name, street, city) • Score (Student_name, Branch_name, marks) • Branch (Branch_name, HOD) • Manages (Student_name, Faculty_name)

asked Dec 10, 2017 in Databases by Tuhin Dutta Loyal (8.5k points) | 130 views

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13

Tuple relational calculus
Student (Student_name, street, city) • Score (Student_name, Branch_name, marks) • Branch (Branch_name, HOD) • Manages (Student_name, Faculty_name) What does the following tuple relational calculus query produce?

asked Dec 10, 2017 in Databases by Tuhin Dutta Loyal (8.5k points) | 93 views

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14

relational calculus

asked Dec 5, 2017 in Databases by Parshu gate Active (5k points) | 133 views

+1 vote

1 answer

15

Relational algebra
Consider the relations r1(P, Q, R) and r2(R, S, T) with primary keys P and R respectively. The relation r1 contains 2000 tuples and r2 contains 2500 tuples. The maximum size of the join r1⋈ r2 is equal to r2⋈ r1 true or false?

asked Dec 3, 2017 in Databases by learner_geek Active (3.6k points) | 239 views

+2 votes

2 answers

16

relational algebra
Consider the following schema: Student (Sid, Sname, age) Course Info (Cid, Cname, Instructor SSN) Enroll (Sid, Cid, grade). The relational algebra expression for “find the Cid’s of courses enrolled by two different students” (no options)

asked Dec 3, 2017 in Databases by shaurya vardhan Active (2.3k points) | 206 views

+1 vote

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17

#dbms query
how to read/breakdown/understand this query? which part wil be solved first? {t∣t∈πR−S(r)∧∀u∈s(∃v∈r(u=v[S]∧t=v[R−S]))}

asked Dec 2, 2017 in Databases by iarnav Loyal (9.3k points) | 45 views

0 votes

1 answer

18

Sql query
Please explain below query step by step and what does it mean?

asked Nov 29, 2017 in Databases by learner_geek Active (3.6k points) | 126 views

+1 vote

0 answers

19

#DBMS Explain these Relational Calculus Queries from GATE Question!

asked Nov 29, 2017 in Databases by iarnav Loyal (9.3k points) | 213 views

0 votes

1 answer

20

TUPLE CALCULUS

asked Nov 6, 2017 in Databases by Parshu gate Active (5k points) | 146 views

+2 votes

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21

self doubt
in the question below in relational algebra if we use projection the relation is considered as a set and hence duplicates are not allowed will even trc and drc follow the same rule ?? rest all i understood only this point is doubtful https://gateoverflow.in/1546/gate2013_35 please clarify

asked Oct 3, 2017 in Databases by Venkat Sai Active (3.5k points) | 85 views

+2 votes

1 answer

22

SQL and Tuple Calculus
Q. Given the relational schema : ENROLL (S#, C#, Section), S# is student number. TEACH (Prof, C#, Section), C# is course number. ADVISE (Prof, S#), Prof is Thesis advisor of S# PRE-REQ (C#, pre-C#), pre-c# is prerequisite course. GRADE ( ... of the same course. (iv) List all students number and course number (v) List the student number and course number who got grade A

asked Aug 26, 2017 in Databases by Tushar Pandey (31 points) | 276 views

+1 vote

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23

stackoverflow
I have to solve the queries using tuple relational calculus and I just want to know if I did them correctly. I'm using this database: EMPLOYEE: fname , minit , lname, ssn , bdate , address , sex , salary , superssn , dno DEPARTMENT: dname dnumber , ... a.Salary > b.Salary))} Any help will be much appreciated. edit: Assume that only one employee can have the highest/lowest salary.

asked Jul 16, 2017 in Databases by shashank023 (469 points) | 157 views

+20 votes

4 answers

24

GATE2017-1-41
Consider a database that has the relation schemas EMP(EmpId, EmpName, DeptId), and DEPT(DeptName, DeptId). Note that the DeptId can be permitted to be NULL in the relation EMP. Consider the following queries on the database expressed in tuple relational calculus. {$t$ | $\exists$u ... ]))} Which of the above queries are safe? I and II only I and III only II and III only I, II and III

asked Feb 14, 2017 in Databases by Arjun Veteran (369k points) | 4.1k views

+1 vote

1 answer

25

Mock Test
Is statement 1 true for all safe expressions ?

asked Jan 24, 2017 in Databases by Harsh181996 Active (4.1k points) | 294 views

+1 vote

1 answer

26

Tuple relational calculus
An undirected simple graph is represented as G(a,b) and a tuple (x,y)€ G if x and y are adjacent vertices. which of the following can not be computed by a TRC query ? (A) Set of vertices who belongs to four length cycle (B) Set of vertices ... zero (C) Set of vertices which belongs to some cycle (D) Set of vertices which have degree n-1 where (n=total number of vertices)

asked Jan 14, 2017 in Databases by Geet (247 points) | 212 views

0 votes

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27

Given the following relational schemas
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? {d.Dname | department(d) ∧ ~ ... (d) ∧ ~ ((∃(s)) student(s) ∧ s.sex = F' ∧ s.deptNo = d.deptId)} None of these

asked Dec 2, 2016 in Databases by Akriti sood Boss (13.7k points) | 219 views

+1 vote

1 answer

28

tuple relational calculus
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)) ... 3. {d.Dname | department(d) ∧ ~ ((∃(s)) student(s) ∧ s.sex = F' ∧ s.deptNo = d.deptId)}

asked Nov 29, 2016 in Databases by vaishali jhalani Loyal (5.9k points) | 432 views

+1 vote

1 answer

29

How does following SQL translates to relational algebra divide operation?

asked Nov 5, 2016 in Databases by GateAspirant999 Active (2.8k points) | 231 views

+3 votes

1 answer

30

Which of the following statements are TRUE/FALSE?

asked Sep 16, 2016 in Programming by GateAspirant999 Active (2.8k points) | 513 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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