(a) Consider again Question 3 in Tutorial 1 (Challenge) to find the restaurants that sell all the pizzas that Maggie likes and don’t sell any pizza that Ralph likes. Write a relational algebra ...

(iii) Suppose the relation Likes contains all information about all customers. In other words, if the pair (cname,pizza) is not in the relation Likes, it means that the customer cname dislikes the ...

Abstract: Query formulation is increasingly performed by systems that need to guess a user's intent (e.g. via spoken word interfaces). But how can a user know that the computational agent is returning ...