RELATIONAL QUERY WRITING in ALGEBRA (AND DATALOG)

Consider a database with the following schema.

LIKES(drinker,beer); /* key: all columns */

FREQUENTS(drinker,pub); /* key: all columns */

SERVES(_pub,beer_,cost); /* key: (pub,beer) */

Consider the following queries:

1. Find drinkers who like at least one expensive (over $8) beer that Joe likes.

2. Find pubs that serve every beer that Joe likes.

3. Find all drinkers who frequent a pub that serves at least 2 beers they like, and one of them for at most $3.

(i) Write RELATIONAL ALGEBRA queries for all of the above

(ii) Also, write DATALOG QUERIES for number 1 and 2.