Principles Of Distributed Database Systems Exercise Solutions //free\\ -

Consider a global relation EMP(ENO, ENAME, TITLE) and PROJ(PNO, PNAME, BUDGET) . There is a relationship relation ASG(ENO, PNO, RESPONSIBILITY, DUR) .

Fragment1 = π_ProjID, Title, ManagerName(PROJECT) Fragment2 = π_ProjID, Budget, StartDate, EndDate(PROJECT) Consider a global relation EMP(ENO, ENAME, TITLE) and

+---------------+ | Fragment 2 | | (Orders) | +---------------+ | | v +---------------+ +---------------+ | Site B | | Site D | | (Replica 1) | | (Replica 2) | +---------------+ +---------------+ In a Primary Copy setup, all updates go

Solutions often utilize a Primary Copy or Voting algorithm. In a Primary Copy setup, all updates go to one master node first. In Voting, a transaction must write to a "quorum" (majority) of replicas to be considered successful, balancing the trade-off between high availability and strict consistency. Conclusion Option 1: (R1 ⨝ S2) then with T3

Find an allocation minimizing total cost.

Option 1: (R1 ⨝ S2) then with T3