A more complicated transaction is to delete the member of staff with a given staff num-ber x, as shown in Figure 20.1(b). In this case, as well as having to delete the tuple in the Staff
relation, we also need to find all the PropertyForRenttuples that this member of staff managed
and reassign them to a different member of staff,newStaffNosay. If all these updates are
not made, referential integrity will be lost and the database will be in an inconsistent state:
a property will be managed by a member of staff who no longer exists in the database.