Recent questions tagged relational-calculus

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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)

asked Apr 11 in Databases by aditi19 Active (2.9k points) | 83 views

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2

ISI2017-PCB-B-3(b)
Consider the following relations: $\text{STD_CHOICES } (\underline{Student\_ID}, \underline{Course\_ID}, Semester)$ and $COURSE\_ASSIGN (\underline{Teacher\_ID}, \underline{Course\_ID}, \underline{Semester})$. The former indicates the choice of courses for ... 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 in Databases by akash.dinkar12 Boss (39k points) | 14 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. ... ))}

asked Mar 30 in Databases by ajaysoni1924 Loyal (9.5k points) | 4 views

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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

asked Mar 27 in Databases by ajaysoni1924 Loyal (9.5k points) | 20 views

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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).

asked Mar 26 in Databases by ajaysoni1924 Loyal (9.5k points) | 18 views

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DBMS Korth Edition 6 Exercise 6 Question 16 (Page No. 254)
Let R = (A, B) and S = (A, C), and let r (R) and s(S) be relations. Write relational-algebra expressions equivalent to the following domainrelational- calculus expressions: a. {< a > | ∃ b (< a, b > ∈ r ∧ b = 17)} b. {< a, b, c > | ... < a, c > ∈ s ∧ ∃ b1, b2 (< a, b1 > ∈ r ∧ < c, b2 > ∈ r ∧ b1 > b2))}

asked Mar 26 in Databases by ajaysoni1924 Loyal (9.5k points) | 23 views

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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)

asked Mar 26 in Databases by ajaysoni1924 Loyal (9.5k points) | 24 views

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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)

asked Mar 26 in Databases by ajaysoni1924 Loyal (9.5k points) | 7 views

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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))}

asked Mar 26 in Databases by ajaysoni1924 Loyal (9.5k points) | 4 views

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10

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.

asked Jan 27 in Databases by Aman Janko (57 points) | 40 views

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11

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….

asked Jan 19 in Programming by shiva0 (229 points) | 39 views

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1 answer

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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, 2018 in Databases by aditi19 Active (2.9k points) | 31 views

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13

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

asked Nov 18, 2018 in Databases by Prince Sindhiya Loyal (6.3k points) | 36 views

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14

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, 2018 in Databases by aditi19 Active (2.9k points) | 27 views

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15

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

asked Oct 28, 2018 in Databases by kumar.dilip Active (5.1k points) | 90 views

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16

doubt
How we find the given calculus is safe or not

asked Sep 8, 2018 in Databases by bhavnakumrawat5 (205 points) | 46 views

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1 answer

17

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, 2018 in Databases by Anand. Active (2.3k points) | 112 views

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18

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 ?

asked Jul 2, 2018 in Databases by Harsh Kumar Active (1.3k points) | 154 views

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1 answer

19

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.

asked Jul 1, 2018 in Databases by Harsh Kumar Active (1.3k points) | 89 views

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1 answer

20

Ace Test Series: DBMS - Relation Algebra

asked Jun 29, 2018 in Databases by Na462 Loyal (8.7k points) | 64 views

+1 vote

2 answers

21

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

asked Apr 15, 2018 in Databases by tarunmaganti (281 points) | 134 views

+3 votes

1 answer

22

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, 2018 in Databases by jothee Veteran (115k points) | 308 views

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23

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, 2018 in Programming by ♥_Less Active (1.1k points) | 107 views

+1 vote

2 answers

24

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, 2018 in Databases by ankit_thawal Active (2.1k points) | 98 views

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25

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 (9.4k points) | 146 views

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26

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 (9.4k points) | 108 views

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27

relational calculus

asked Dec 5, 2017 in Databases by Parshu gate Active (5.1k points) | 166 views

+1 vote

1 answer

28

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 (3.7k points) | 270 views

+2 votes

2 answers

29

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 (2.4k points) | 264 views

+1 vote

0 answers

30

#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 (9.7k points) | 51 views

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