Recent questions tagged relational-algebra / GATE Overflow for GATE CSE

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151

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

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

kumar.dilip

544 views

kumar.dilip asked Oct 27, 2018

1 votes

0 answers

152

Gateforum Test Series: Databases - Relational Algebra
C is provided as the answer. Statement P, I understand but why S is also correct?

C is provided as the answer. Statement P, I understand but why S is also correct?

Gupta731

444 views

Gupta731 asked Oct 24, 2018

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0 answers

153

GateForum Test Series: Databases - Relational Algebra
I think the answer should be A, but C is given as the answer.

I think the answer should be A, but C is given as the answer.

Gupta731

284 views

Gupta731 asked Oct 24, 2018

1 votes

0 answers

154

Test Series
Consider a relation R(A, B) that contains r tuples, and a relation S(B, C) that contains s tuples; assume r > 0 and s > 0. Make no assumptions about keys. For the following relational algebra expression, in terms of r and s the minimum and ... result? given answer is: minimum:0, maximum: min(r,s) according to me: minimum:0, maximum: r please give answer with proper explanation.

Consider a relation R(A, B) that contains r tuples, and a relation S(B, C) that contains s tuples; assume r 0 and s 0. Make no assumptions about keys. For the following...

aambazinga

775 views

aambazinga asked Oct 24, 2018

0 votes

1 answer

155

How to know which type of join shall I apply in dbms relational algebra?
I'm confused when to you which join and cross product. Please help me

I'm confused when to you which join and cross product. Please help me

Fida

593 views

Fida asked Oct 18, 2018

0 votes

1 answer

156

Relational Algebra
In relational algebra query , it always remove duplicates, So, do we need to use cross product always, in place of join or union operation ? If not , then where exactly we use join or union operation ?

In relational algebra query , it always remove duplicates,So, do we need to use cross product always, in place of join or union operation ? If not , then where exactly we...

srestha

1.4k views

srestha asked Oct 10, 2018

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0 answers

157

DBMS doubt
Can someone derive it with table https://gateoverflow.in/242014/dbms-raghu-ramakrishnan?show=243128 I am still unable to get proper answer by hand

Can someone derive it with tablehttps://gateoverflow.in/242014/dbms-raghu-ramakrishnan?show=243128I am still unable to get proper answer by hand

srestha

365 views

srestha asked Oct 6, 2018

0 votes

1 answer

158

test series

Rudra Pratap

437 views

Rudra Pratap asked Sep 30, 2018

1 votes

2 answers

159

ISI2017-PCB-CS-3-a
Let $R(A,B,C)$ be a relation with primary key $(A)$ and $S(A, D, E)$ a relation with primary key $(A, D)$. Each of the relations has $n$ tuples. If the number of tuples in $R \: \text{ natural join } S$ is $m$, then determine the number of tuples in $R$ $\text{ natural left outer join } S$.

Let $R(A,B,C)$ be a relation with primary key $(A)$ and $S(A, D, E)$ a relation with primary key $(A, D)$. Each of the relations has $n$ tuples. If the number of tuples i...

go_editor

503 views

go_editor asked Sep 20, 2018

0 votes

1 answer

160

MadeEasy Workbook: Databases - Relational Algebra
Caption Can plz any one give solutions of e,f,g,h in relational algebra?

CaptionCan plz any one give solutions of e,f,g,h in relational algebra?

mobashshir

1.7k views

mobashshir asked Aug 19, 2018

0 votes

1 answer

161

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

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='...

Anand.

689 views

Anand. asked Aug 17, 2018

1 votes

2 answers

162

Procedural And Non Procedural Query
What is the difference between procedural query language and non-procedural query language? Why Relation algebra is called procedural and TRC is called non-procedural?

What is the difference between procedural query language and non-procedural query language? Why Relation algebra is called procedural and TRC is called non-procedural?

Jason

1.8k views

Jason asked Jul 20, 2018

0 votes

0 answers

163

Natural Join
Consider two relations R(A, B, C) and S(B, D) with R contains 5000 tuples stored in a sequential file sorted on attribute A and S contain 100000 tuples stored in a sequential file sorted on attribute B. Each block can hold 10 R tuples or 10 S tuples. Which one of the following index is most appropriate for answering query R (natural Join) S (Assume index always stored in memory)

Consider two relations R(A, B, C) and S(B, D) with R contains 5000 tuples stored in a sequential file sorted on attribute A and S contain 100000 tuples stored in a sequen...

Na462

772 views

Na462 asked Jul 14, 2018

0 votes

1 answer

164

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.

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...

Harsh Kumar

471 views

Harsh Kumar asked Jul 1, 2018

0 votes

1 answer

165

Ace Test Series: DBMS - Relation Algebra

Na462

657 views

Na462 asked Jun 29, 2018

2 votes

3 answers

166

MadeEasy Test Series: Databases - Relational Algebra
Consider relation R' and S' have n' and m' tuples, respectively. Choose the best matching between List-I (Expression) and List-II (Maximum number of tuple): Soln. According to me Answer should be Option C. 1.R union S = m+n (easy nothing to say) 2 ... 3 3 3 5 4 3 3 3 6 Now in R natual join S = m * n So option C should suffice isn't it ?

Consider relation ‘R’ and ‘S’ have ‘n’ and ‘m’ tuples, respectively. Choose the best matching between List-I (Expression) and List-II (Maximum number of t...

Na462

2.8k views

Na462 asked Jun 14, 2018

0 votes

0 answers

167

DBMS- Relational Algebra
If R1 with N1 tuples and R2 with N2 tuples are two relations which are not union compatible the number of tuples in R1 union R2 is?

If R1 with N1 tuples and R2 with N2 tuples are two relations which are not union compatible the number of tuples in R1 union R2 is?

Hakuna Matata

870 views

Hakuna Matata asked May 15, 2018

0 votes

0 answers

168

Understanding theta join operation
Q.1. Does theta join operator requires following union compatibility requirements?: Same number of columns Domain of corresponding columns should be same I feel no, since I came across following fact: $\sigma_\theta( R_1\times R_2)=R_1⋈_\theta R_2$ ... as shown above, does it mean columns of resultant relation will contain ALL columns from both $R_1$ and $R_2$?

Q.1. Does theta join operator requires following union compatibility requirements?:Same number of columnsDomain of corresponding columns should be sameI feel no, since I ...

GateAspirant999

643 views

GateAspirant999 asked May 12, 2018

0 votes

1 answer

169

DBMS Relational Algebra
Which of the following Queries is more Efficient on the given data? 1. In terms of Space. 2. In terms of Calculation. also, How many calculations are necessary for Each?

Which of the following Queries is more Efficient on the given data?1. In terms of Space.2. In terms of Calculation. also, How many calculations are necessary for Each?

slowpoke

431 views

slowpoke asked Mar 20, 2018

0 votes

0 answers

170

Database Management Systems by Raghu Ramakrishnan, Johannes Gehrke ~ 2nd edition Q4.3.5
Given schema: $Suppliers$ ($sid:$ integer$, $sname:$ $string$, $address:$ $string$) $Parts$ ($pid:$ $integer$, $pname:$ $string$, $color:$ $string$) $Catalog$ ( $sid:$ $integer,$ $pid:$ $integer,$ $cost:$ $real$) Find the $ ... $ $\{<A> $|Ǝ(A,D,G)∈ Catalog$ ^ $∀(D,E,F)∈ Parts\}$

Given schema:$Suppliers$ ($sid:$$ integer$, $sname:$ $string$, $address:$ $string$)$Parts$ ($pid:$ $integer$, $pname:$ $string$, $color:$ $string$)$Catalog$ ( $sid:$ $int...

Aman Janko

1.0k views

Aman Janko asked Mar 11, 2018

0 votes

4 answers

171

Uttrakhand Asst. Professor Exam-51
Which of the following operation of relational algebra, selects certain columns from the table and discards the other columns? SELECT PROJECT DIVISION None of the above

Which of the following operation of relational algebra, selects certain columns from the table and discards the other columns?SELECTPROJECTDIVISIONNone of the above

gatecse

606 views

gatecse asked Mar 2, 2018

48 votes

4 answers

172

GATE CSE 2018 | Question: 41
Consider the relations $r(A, B)$ and $s(B, C)$, where $s.B$ is a primary key and $r.B$ is a foreign key referencing $s.B$. Consider the query $Q: r \bowtie (\sigma_{B<5} (s))$ Let LOJ denote the natural left outer-join operation. Assume that $r$ and $s$ contain no null ... $r \: LOJ \: (\sigma_{B<5} (s))$ $\sigma_{B<5} (r) \: LOJ \: s$

Consider the relations $r(A, B)$ and $s(B, C)$, where $s.B$ is a primary key and $r.B$ is a foreign key referencing $s.B$. Consider the query$Q: r \bowtie (\sigma_{B<5} (...

gatecse

15.7k views

gatecse asked Feb 14, 2018

0 votes

0 answers

173

GeeksForGeeks Mock test 1 2017: Databases - Relational Algebra
Consider the following collection of relation schemes: professor(profname, deptname) department(deptname, building) committee(profname,commname) Find all the professors who are in exactly (i.e., no more and no less) all those committees ... Smith(committee)) R3 <- Πcommname(committee) - R2 (committee / R2) - Πprofname(committee ⋈ R3)

Consider the following collection of relation schemes:professor(profname, deptname) department(deptname, building) committee(profname,commname) Find all the professors wh...

Utsav09

737 views

Utsav09 asked Feb 1, 2018

1 votes

1 answer

174

MadeEasy Test Series 2018: Databases - Relational Algebra
Consider the following database table Supplier (Sid, Sname, rating) Parts (Pid, Pname, color) Catalog (Sid Pid, cost) Which of the following SQL query correct representation to retrieve Sid’s who supplied every red part.

Consider the following database tableSupplier (Sid, Sname, rating)Parts (Pid, Pname, color)Catalog (Sid Pid, cost)Which of the following SQL query correct representation ...

nikkey123

1.7k views

nikkey123 asked Jan 29, 2018

1 votes

1 answer

175

Natural join
My answer is not matching with any of the option.so what is the correct answer

My answer is not matching with any of the option.so what is the correct answer

learner_geek

1.3k views

learner_geek asked Jan 24, 2018

2 votes

0 answers

176

MadeEasy Test Series 2018: Databases - Relational Algebra
Hello, I always have trouble solving queries where the inner most query is referring to the main query. Can someone please explain how the result is obtained for the following question. Thank You The provided answer is: Age more than 30 and not works for every project with project name database

Hello,I always have trouble solving queries where the inner most query is referring to the main query. Can someone please explain how the result is obtained for the follo...

Aman Krishna

553 views

Aman Krishna asked Jan 23, 2018

1 votes

1 answer

177

MadeEay Test Series 2018: Databases - Relational Algebra
here for 1st relation algebra operation the join operation is given without condition , will it be considered as natural join or cartesian product?

here for 1st relation algebra operation the join operation is given without condition , will it be considered as natural join or cartesian product?

charul

412 views

charul asked Jan 16, 2018

2 votes

0 answers

178

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 ?

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 ...

♥_Less

435 views

♥_Less asked Jan 14, 2018

2 votes

0 answers

179

Relational Algebra
what does this uniform distribution means?

what does this uniform distribution means?

Pawan Kumar 2

332 views

Pawan Kumar 2 asked Jan 12, 2018

6 votes

2 answers

180

Full Outer Join
Why is the minimum number of tuples in full outer join equal to max (m,n) ?

Why is the minimum number of tuples in full outer join equal to max (m,n) ?

hacker16

3.8k views

hacker16 asked Jan 9, 2018

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