CS计算机代考程序代写 Q1

Q1
Q2
Exercise 2 – Solution
!π{name,subj}(σ(mark>70)(STUDENT ⋈(sid=stude) MARK)) Q3
Q4
A ← π{authorID}author − π{authorID}book B ← π{firstName,lastName}(A ⋈ author)
(It’s possible to have duplicate author names) Q5
Q6
Q7
A ← π{authorID}book
B ← π{authorID}authorPub
!C ← π{firstName,lastName}((A − B) ⋈ author)
Q8

Q9
Q10