Relationsalgebra÷vning (Databasteknik II)

Adapted from Elmasri, Navathe: Fundamentals of Database Systems, 3d Ed, exercise 7.25.

A company has a database to keep track of the travel expenses of its salespersons. The database contains the following relations:

Salesperson(SSN, Name, StartYear, DeptNo)
Trip(SSN, FromCity, ToCity, DepartureDate, ReturnDate, TripId)
Expense(TripId, Account, Amount)
Note: The cost of a trip is split among one or more accounts. To find the cost of one trip, you have to add the amounts on that trip's rows in the Expense relation.


Thomas Padron-McCarthy (, 11 februari 2007