SQL

(a) How is redundancy reduced in the following models?

 (i) Hierarchical
 (ii) Network
 (iii) Relational 

Write a one line answer in each case.

(b) Suppose we have a database consisting of the following three relations:

 FREQUENTS       (CUSTOMER, HOTEL)
 SERVES          (HOTEL, SNACKS)
 LIKES           (CUSTOMER, SNACKS) 

The first indicates the hotels each customer visits, the second tells which snacks each hotel serves and the last indicates which snacks are liked by each customer. Express the following query in relational algebra: print the hotels that serve a
snack that customer Rama likes.