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Gate 2008 IT DBMS Relational Please help with this question . Stud...
Gate 2008 IT DBMS Relational
Please help with this question .

Student (school-id, sch-roll-no, sname, saddress)
School (school-id, sch-name, sch-address, sch-phone)
Enrolment(school-id sch-roll-no, erollno, examname)
ExamResult(erollno, examname, marks)

Consider the following tuple relational calculus query.
{t | ∃ E ∈
Enrolment t = E.school-id ∧
| {x | x ∈ Enrolment ^ x.school-id = t ∧

(∃ B ∊ ExamResult B.erollno = x.erollno ∧
B.examname = x.examname ∧

B.marks > 35)}| /

| {x | x ∊ Enrolment ∧

x.school-id = t}| * 100 > 35}
If a student needs to score more than 35 marks to pass an exam, what does the query return?

a The empty set
b schools with more than 35% of its students enrolled in some exam or the other
c schools with a pass percentage above 35% over all exams taken together
d schools with a pass percentage above 35% over each exam

4Comments
Apoorva Jain @apoorvaj1
17 Dec 2018 12:39 pm
@ranita mam plz help
Pritam Prasun @pritam
23 Dec 2018 03:58 pm
Apoorva, Please correct the question. It seems to have many typos.
Rajesh @rajeshrajput1
9 Feb 2019 02:00 pm
b
preeti @preetii
2 Dec 2019 12:10 pm
Nice
Transaction Management, Files ​:- 1st Dec - 2018

Hi there,

As per the Virtual GATE - '19 Schedule, classroom discussion will be about Memory Management.

Please follow the links below for a better understanding of the said topic and post your Doubts and Queries.

You can also post Examples and Notes to help your Peers.

Transaction Management :- https://www.techtud.com/chapter/transaction-management

Files :- https://www.techtud.com/chapter/files

Quiz :- https://www.techtud.com/quiz/file-structure

0Comment
Process Synchronisation :- 24th Nov - 2018

Hi there,

As per the Virtual GATE - '19 Schedule, classroom discussion will be about Process Synchronisation.

Please follow the links below for a better understanding of the said topic and post your Doubts and Queries.

You can also post Examples and Notes to help your Peers.

Process Synchronisation :-

0Comment
Process Management :- 23th Nov - 2018

Hi there,

As per the Virtual GATE - '19 Schedule, classroom discussion will be about Process Management.

Please follow the links below for a better understanding of the said topic and post your Doubts and Queries.

You can also post Examples and Notes to help your Peers.

  • Process Management :-

Introduction to Operating System:- https://www.techtud.com/chapter/introduction-operating-system

Process Management:- https://www.techtud.com/chapter/process-management

0Comment
ALU, DMA, I/O - 21th Oct, 2018

Hi there,

As per the Virtual GATE - '19 Schedule, today's classroom discussion will be about  ALU, DMA, I/O .

Please follow the links below for a better understanding of the said topic and post your Doubts and Queries.

You can also post Examples and Notes to help your Peers.

0Comment
Maths-2 VirtualGATE is postponed

Hello all,

This is to inform you that the maths-2 test will be delayed for a day. We will announce the status by tomorrow.

Actually, the idea is to move the test from http://virtualgate.in to Techtud itself so that we can involve more into the discussion, bookmark specific question for later revision and most of all attempt the test in GATE environment.

The development team is about to finalize the development and hence we have decided to delay this test a bit. However, you are encouraged to keep preparing at the proper pace.

Trust me, the delay is for the greater good.

Below is what is coming:

1Comment
Abhishek Shaw @abhishekshaw
19 Oct 2018 03:04 pm
@pritam Sir any update ?
Machine instructions and addressing modes - 20th Oct, 2018

Hi there,

As per the Virtual GATE - '19 Schedule, today's classroom discussion will be about  Machine instructions and addressing modes .

Please follow the links below for a better understanding of the said topic and post your Doubts and Queries.

You can also post Examples and Notes to help your Peers.

 

0Comment
VirtualGATE 2019 Schedule is out!!

The schedule is planned keeping the following things in mind: -

  • We cover all the important topics with a balanced focus
  • All tests run during the weekend as well
  • Assuming the GATE to be held on 1-2 Feb, we must finish the syllabus by Jan 10th
  • Last 20 days for grand revision
  • 2 Full-length VirtualGATE
11Comments
manish jain @manishjain1
14 Sep 2018 07:12 pm
today's online class?
Pritam Prasun @pritam
14 Sep 2018 07:29 pm
The Class Room has been started and the link and the secret key has already been shared with the selected students.
mohit sharma @mohitjarvissharma
14 Sep 2018 07:35 pm
But sir, I received the selection email but didn't receive the secret key. I don't want to miss the classes.
manish jain @manishjain1
14 Sep 2018 07:41 pm
check your mail id
akshat @akshats063
14 Sep 2018 07:40 pm
yes sir i also didnt receive the secret key i have been shortlisted
Pritam Prasun @pritam
14 Sep 2018 07:44 pm
let me forward it again.
mohit sharma @mohitjarvissharma
14 Sep 2018 07:48 pm
Sir, I registered with a different email id on this link: https://www.techtud.com/virtualgate/2019/registration. But my virtual gate account is on another id. Can this be an issue for not receiving the second email?
akshat @akshats063
14 Sep 2018 07:52 pm
ok i got the mail Thank you sir
Sushma @sushma9
14 Sep 2018 10:06 pm
Sir, I didn't receive the secret key.
Pritam Prasun @pritam
15 Sep 2018 12:19 am
Please send me your email address with which you attended the test. I will verify and resend the code.
Adeema jain @adeema
15 Sep 2018 11:30 am
Can i give the classroom selection test now?