Consider the following table definition, where the primary keys are underlined. Give an expression in relational algebra for each of the following queries. Athlete (aID integer, aName string, ranking integer, age integer) Event (eID string, eName string, eLocation string) Competes (aID integer, eID string, sport string, year integer)

5. Find the names of athletes who have competed in Dew Tour or VPS

6. Find the names of athletes who have competed in both Dew Tour and VPS

7. Find the aID of athletes over the age of 14 who have not competed in VPS

8. Find the names of any athletes who competed in all events

9. Find the athletes who are older than 19 years old.