Consider The Following Relational Scheme

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 ∈ ExamResult B.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?

Let $$R\left( {A,\,B,\,C,\,D,E,P,G} \right)$$ be a relational schema in which the following functional dependencies are known to hold: $$AB \to CD,\,\,DE \to P,\,\,C \to E.\,\,P \to C$$ and $$B \to G.$$ The relational schema $$R$$ is

Let $$R\left( {A,B,C,D} \right)$$ be a relational schema with the following functional dependencies:
$$A \to B,\,\,B \to C,\,\,C \to D$$ and $$D \to B.$$
The decomposition of $$R$$ into $$(A,B), (B,C)$$ and $$(B,D)$$

Consider the following relational schemes for a library database. Book ( Title, Author, Catalog_ no, Publisher, Year, Pr ice ) Collection ( Title, Author, Catalog no )
With in the following functional dependencies:
$${\rm I}.\,\,\,\,\,\,$$ Title Author $$ \to $$ Catalog_no
$${\rm II}.\,\,\,\,$$ Catalog_no $$ \to $$ Title Author Publisher Year
$${\rm III}.\,\,\,\,$$ Publisher Title Year $$ \to $$ Price

Assume { Author, Title } is the key for both schemes. Which of the following statements is true?