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Recent questions tagged relational-calculus

1 votes
2 answers
33
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)
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 alw...
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0 votes
0 answers
34
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)
What does the following tuple relational calculus query produce?• Student (Student_name, street, city)• Score (Student_name, Branch_name, marks)• Branch (Branch_nam...
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35
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?
Student (Student_name, street, city)• Score (Student_name, Branch_name, marks)• Branch (Branch_name, HOD)• Manages (Student_name, Faculty_name)What does the followi...
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2 votes
1 answer
37
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?
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 s...
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2 votes
3 answers
38
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)
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...
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1 votes
0 answers
39
#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]))}
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]))}
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0 votes
1 answer
40
Sql query
Please explain below query step by step and what does it mean?
Please explain below query step by step and what does it mean?
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1 votes
1 answer
48
Mock Test
Is statement 1 true for all safe expressions ?
Is statement 1 true for all safe expressions ?
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0 votes
1 answer
56
tuple calculas
can anyone provide me best source from where i can learn tuple calculas from starting. thanx in advance
can anyone provide me best source from where i can learn tuple calculas from starting.thanx in advance
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1 votes
1 answer
57
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 :
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 loo...
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2 votes
2 answers
59
Tuple Relational Calculus
I believe since the variable 't' is a free variable, so option three should also be right. Second option is also correct?
I believe since the variable 't' is a free variable, so option three should also be right. Second option is also correct?
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