Recent questions tagged relational-calculus

0 votes

1 answer

1

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 18 hours ago in Databases by Anand. Active (2.1k points) | 21 views

0 votes

1 answer

2

Tuple Relational Calculus Query - Confirm the Answer

asked Jul 2 in Databases by Harsh Kumar Junior (587 points) | 50 views

0 votes

1 answer

3

Tuple relational calculus - Seeking advice

asked Jul 1 in Databases by Harsh Kumar Junior (587 points) | 43 views

0 votes

2 answers

4

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

asked Apr 15 in Databases by tarunmaganti (265 points) | 82 views

+2 votes

1 answer

5

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 (99.8k points) | 216 views

+2 votes

0 answers

6

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) | 74 views

+1 vote

2 answers

7

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) | 79 views

0 votes

0 answers

8

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 (7.9k points) | 117 views

0 votes

0 answers

9

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 (7.9k points) | 79 views

0 votes

0 answers

10

relational calculus

asked Dec 5, 2017 in Databases by Parshu gate Active (4.9k points) | 108 views

+1 vote

1 answer

11

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 (3.5k points) | 181 views

+2 votes

2 answers

12

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 (2.2k points) | 163 views

+1 vote

0 answers

13

#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 (7.9k points) | 35 views

0 votes

1 answer

14

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

asked Nov 29, 2017 in Databases by learner_geek Active (3.5k points) | 118 views

+1 vote

0 answers

15

#DBMS Explain these Relational Calculus Queries from GATE Question!

asked Nov 29, 2017 in Databases by iarnav Loyal (7.9k points) | 181 views

0 votes

1 answer

16

TUPLE CALCULUS

asked Nov 6, 2017 in Databases by Parshu gate Active (4.9k points) | 125 views

+2 votes

0 answers

17

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 (3.3k points) | 78 views

+2 votes

1 answer

18

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) | 241 views

+1 vote

0 answers

19

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 (427 points) | 140 views

+18 votes

4 answers

20

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 (355k points) | 3.5k views

+1 vote

1 answer

21

Mock Test
Is statement 1 true for all safe expressions ?

asked Jan 24, 2017 in Databases by Harsh181996 Active (4k points) | 265 views

+1 vote

1 answer

22

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) | 191 views

0 votes

0 answers

23

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 (13.6k points) | 204 views

0 votes

1 answer

24

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 (5.8k points) | 379 views

+1 vote

1 answer

25

How does following SQL translates to relational algebra divide operation?

asked Nov 5, 2016 in Databases by GateAspirant999 Active (2.6k points) | 209 views

+3 votes

1 answer

26

Which of the following statements are TRUE/FALSE?

asked Sep 16, 2016 in Programming by GateAspirant999 Active (2.6k points) | 475 views

0 votes

2 answers

27

Which Tuple Relation calculus query is correct?

asked Aug 21, 2016 in Databases by GateAspirant999 Active (2.6k points) | 200 views

0 votes

1 answer

28

tuple calculas
can anyone provide me best source from where i can learn tuple calculas from starting. thanx in advance

asked May 20, 2016 in Databases by Sourabh Kumar Active (1.9k points) | 112 views

+1 vote

1 answer

29

Relational Calculus basic
Hi , i have just written the question and answer for the below schema . I have written this according to lectures of IIT KGP . I would request all the experts please look to my solution and point out my mistakes (if any ) :) page 1 Page 2 : page 3 : page 4 :

asked Apr 22, 2016 in Databases by Dexter Loyal (9.6k points) | 279 views

+1 vote

1 answer

30

relational calculus
BOOK(ACC_NO, TITLE, YR_PUB) USER(CARD_NO, B_NAME, B_ADD) B_BY(ACC_NO , CARD_NO , DOI) SUPPLIER(S_NAME,S_ADD) S_BY(S_NAME,S_NAME,PRICE,,DOS) Query :- find the names of those supplier who have supplied titles corresponding to all book issused by 'VIJAY'. using relational calculus solve the query (if possible give proper explation)

asked Apr 16, 2016 in Databases by indrajeet Active (2k points) | 201 views

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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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