Calsswork
Database Systems Lab
CSE414
Submitted to:
Dr. Rudra Pratap Deb Nath
Associate Professor
Department of Computer Science and Engineering
University of Chittagong
Submitted by:
Md. Kais
20701003
Department of Computer Science and Engineering
University of Chittagong
November 22, 2022
20701003
3.1
a.
πperson_name (σcity="miami" (employee))
b.
πperson_name (σsalary>10000 (works))
c.
πperson_name (σcity="miami ∩ salary>10000 (employee ⋈ works))
3.2
a.
πperson_name (σcompany_name="F irst B ank cooperation" (works))
b.
πperson_name,city (σcompany_name="F irst B ank cooperation" (works ⋈ employee))
c.
πperson_name,city,salary (σcompany_name="F irst B ank cooperation" ∩ salary>10000 (works ⋈ employee))
d.
πperson_name ((works ⋈ employee ⋈ company))
e.
πperson_name,city,salary (company ÷ πcompany_name="S mall B ank cooperation" (company))
3.3
a.
πperson_name (σe.manager_name=m.person_name ∧ e.city=m.city ∧ e.street=m.street(ρe employee ⋈ manages×ρm (employee)) )
b.
πperson_name (σcompany_name 
= "F irst B ank cooperation" (works))
3.4
a.
γcompany_name,count(∗)(works)
b.
t1 ← company_nameβavg Salary(works)
t2 ← σcompany_name="F irst B ank cooperation"(t1)
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