Question 22

$EMPLOY\acute{E}2={\rho }_{Dept\to Dept2,Pourcent\to Pourcent2}(EMPLOY\acute{E})$

${\pi }_{\{NrEmp\}}({\sigma }_{Dept\ne Dept2}({\sigma }_{Pourcent=50}({\sigma }_{Pourcent2=50}(EMPLOY\acute{E}\bowtie Dept2))))$

@allow <>
% base de données question 6
 
@let EMPLOYE = @relation [NrEmp, Dept, Pourcent] {
  < E1, Info, 40  >
  < E1, Bio , 60  >
  < E2, Eco , 100 >
  < E3, Bio , 50  >
  < E3, Eco , 50  >
  < E4, Eco , 100 >
  < E5, Eco , 50  >
  < E5, Bio , 25  >
  < E5, Info, 25  >
}
 
@let DEPARTEMENT = @relation [NomDept, Budget, Chef] {
  < Info, 5000, E1 >
  < Bio , 3500, E1 >
  < Eco , 4000, E5 >
}
 
@let EMPLOYE2 = @rename{Dept: Dept2, Pourcent: Pourcent2}(EMPLOYE)
 
@let result = @project {NrEmp}(@select{Dept<>Dept2}@select{Pourcent="50"}@select{Pourcent2="50"}(EMPLOYE @join EMPLOYE2))
 
@print result