Recent questions tagged relational-calculus

Recent questions tagged relational-calculus

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NIELIT 2016 MAR Scientist B - Section C: 42
The relational algebra expression equivalent to the tuple calculus expression $\{t\mid t \in r \land (t[A]=10 \land t[B]=20)\}$ is $\sigma_{(A=10\:\lor\:B=20)}(r)$ $\sigma_{(A=10)}(r)\cup\sigma_{(B=20)}(r)$ $\sigma_{(A=10)}(r)\cap\sigma_{(B=20)}(r)$ $\sigma_{(A=10)}(r)-\sigma_{(B=20)}(r)$

Lakshman Patel RJIT asked in Databases Mar 31, 2020

by Lakshman Patel RJIT

452 views

1 vote

1 answer

2

NIELIT 2017 July Scientist B (IT) - Section B: 19
If $R$ is a relation in Relational Data Model and $A_1,A_2,\dots A_n$ are the attributes of relation $R$, what is the cardinality of $R$ ...

Lakshman Patel RJIT asked in Databases Mar 30, 2020

by Lakshman Patel RJIT

292 views

4 votes

5 answers

3

UGCNET-June-2019-II: 31
Which of the following has same expressive power with regard to relational query language? Rational algebra and domain relational calculus Relational algebra and tuples relational calculus Relational algebra and domain relational calculus restricted to safe expression Relational algebra and ... restricted to safe expression a and b only c and d only a and c only b and d only

Arjun asked in Databases Jul 2, 2019

by Arjun

1.9k views

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1 answer

4

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

aditi19 asked in Databases May 8, 2019

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1 answer

5

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?

aditi19 asked in Databases May 7, 2019

456 views

4 votes

3 answers

6

Raghuramkrishnan Exercise 4.1 Relational Algebra
Given two relations R1 and R2, where R1 contains N1 tuples, R2 contains N2 tuples, and N2>N1> 0, give the minimum and maximum possible sizes (in tuples) for the result relation produced by each of the following relational algebra expressions. In each ... $σa=5(R1)$ (selection) $\pi a(R1)$ (projection) $R1/R2$ (division)

aditi19 asked in Databases Apr 11, 2019

4.2k views

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0 answers

7

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.

akash.dinkar12 asked in Databases Apr 8, 2019

by akash.dinkar12

363 views

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DBMS Korth Edition 6 Exercise 6 Question 17 (Page No. 254)
Let R = (A, B) and S = (A, C), and let r (R) and s(S) be relations. Write SQL Queries equivalent to the following domain relational- calculus expressions: a. {< a > | $\exists b (< a, b > \epsilon¸r \wedge b$ = 17)} b. ... ))}

ajaysoni1924 asked in Databases Mar 30, 2019

by ajaysoni1924

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0 votes

1 answer

9

DBMS Korth Edition 6 Exercise 6 Question 18 (Page No. 254)
Let R = (A, B) and S = (A, C), and let r (R) and s(S) be relations. Using the special constant null, write tuple-relational-calculus expressions equivalent to each of the following: a. r $ROJ$ s b. r $FOJ$ s c. r $LOJ$ s

ajaysoni1924 asked in Databases Mar 27, 2019

by ajaysoni1924

279 views

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10

DBMS Korth Edition 6 Exercise 6 Question 19 (Page No. 254)
Give a tuple-relational-calculus expression to find the maximum value in relation r (A).

ajaysoni1924 asked in Databases Mar 26, 2019

by ajaysoni1924

335 views

1 vote

0 answers

11

DBMS Korth Edition 6 Exercise 6 Question 15 (Page No. 253-254)
Consider the employee database shown here. Give expressions in tuple relational calculus and domain relational calculus for each of the following queries: a. Find the names of all employees who work for First Bank Corporation . b ... (person name, company name, salary) company (company name, city) manages (person name, manager name)

ajaysoni1924 asked in Databases Mar 26, 2019

by ajaysoni1924

341 views

1 vote

1 answer

12

DBMS Korth Edition 6 Exercise 6 Question 8 (Page No. 251)
Consider the relational database given below where the primary keys are underlined. Give an expression in tuple relational calculus for each of the following queries: a. Find all employees who work directly for Jones. b. Find all ... works (person name, company name, salary) company (company name, city) manages (person name, manager name)

ajaysoni1924 asked in Databases Mar 26, 2019

by ajaysoni1924

649 views

0 votes

0 answers

13

DBMS Korth Edition 6 Exercise 6 Question 7 (Page No. 251)
Let R = (A, B) and S = (A,C), and let r (R) and s(S) be relations.Write expressions in relational algebra for each of the following queries: a. {< a > | ∃ b (< a, b > ∈ r ∧ b = 7)} b. {< a, b, c > | < a, b > ∈ r ∧ < ... | ∃ c (< a, c > ∈ s ∧ ∃ b1, b2 (< a, b1 > ∈ r ∧ < c, b2 > ∈ r ∧ b1 > b2))}

ajaysoni1924 asked in Databases Mar 26, 2019

by ajaysoni1924

143 views

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14

DBMS Korth Edition 6 Exercise 6 Question 6 (Page No. 251)
Let R = (A, B, C), and let r1 and r2 both be relations on schema R. Give an expression in the domain relational calculus that is equivalent to each of the following: a. $\prod _A(r1)$ b. $\sigma _{B =17} (r1)$ c. r1 ∪ r2 d. r1 ∩ r2 e. r1 − r2 f. $\prod _{A,B}(r1) \Join \prod _{B,C}(r2)$

ajaysoni1924 asked in Databases Mar 26, 2019

by ajaysoni1924

558 views

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1 answer

15

Relational algebra and SQL
SQL Aggregation is possible by extended relational algebra operators? SQL grouping is possible in relational algebra. Relational algebra is equivalent to safe relational calculus expressions, then grouping and aggregation possible in tuple relational calculus ... calculus? What about ordering? Please explain how will we consider these questions from GATE point of view.

Aman Janko asked in Databases Jan 27, 2019

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0 answers

16

UGC-NET CS 2016 question
Given i= 0, j = 1, k = – 1 x = 0.5, y = 0.0 What is the output of given ‘C’ expression ? x * 3 & & 3 || j | k explanation please….

shiva0 asked in Programming Jan 19, 2019

by shiva0

239 views

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1 answer

17

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?

aditi19 asked in Databases Nov 26, 2018

261 views

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0 answers

18

Zeal Workbook: Databases - Relational Calculus
Answer is all Doubt ---how (1,4) is present in O/p

Prince Sindhiya asked in Databases Nov 18, 2018

by Prince Sindhiya

130 views

0 votes

1 answer

19

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

aditi19 asked in Databases Nov 4, 2018

102 views

0 votes

0 answers

20

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

kumar.dilip asked in Databases Oct 28, 2018

288 views

0 votes

0 answers

21

doubt
How we find the given calculus is safe or not

bhavnakumrawat5 asked in Databases Sep 8, 2018

by bhavnakumrawat5

129 views

0 votes

1 answer

22

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 $\prod \text{Room no,hotel no,type,price}(\sigma \text{type='single' } \wedge \text{price=200 })$

Anand. asked in Databases Aug 17, 2018

by Anand.

306 views

1 vote

2 answers

23

Tuple Relational Calculus Query - Confirm the Answer
Relation Schema : Employee (Name, Ssn, Bdate, Address, Dept_number) Project (Pname, Pno, Dept_number) WorksOn (Essn, Pno, Hours) List the names of employees who work on all the projects controlled by department number 10. My Answer : ... name will be printed who work for some project at department no. 5 and not for the department no. 10 ?

Harsh Kumar asked in Databases Jul 2, 2018

865 views

0 votes

1 answer

24

Tuple relational calculus - Seeking advice
I am not well versed in Predicate calculus and maybe, therefore, I am having problems writing queries in Tuple Relational Calculus and sometimes also in interpreting them. I want to know if there is any specific and definite procedure of ... of good books/lectures on predicate calculus. Any guidance or reference would be highly helpful for me. Thank You.

Harsh Kumar asked in Databases Jul 1, 2018

278 views

0 votes

1 answer

25

Ace Test Series: DBMS - Relation Algebra

Na462 asked in Databases Jun 29, 2018

by Na462

248 views

1 vote

2 answers

26

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

tarunmaganti asked in Databases Apr 15, 2018

by tarunmaganti

400 views

8 votes

1 answer

27

GATE CSE 1993 | Question: 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 $ \text{*'}.$ ... it is in $\text{3NF}$. If not, normalize the relations so that they are in $\text{3NF}$ (without proving).

jothee asked in Databases Feb 5, 2018

by jothee

1.4k views

2 votes

0 answers

28

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 ?

♥_Less asked in Programming Jan 14, 2018

239 views

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