1. Relational Model MOVIES (id, title, yr, score, votes, director) ACTORS (id, name) CASTINGS (movieid, actorid, ord) DIRECTORS(id, name) A movie is described by an identifier (integer, key of the table), a title, a year (first release of the movie), a score (average of all votes cast for the movie), a number of votes and a director (integer, foreign key to id in DIRECTORS). An actor is described by an identifier (integer, key of the table) and a name. An actor may play a role in zero to several movies and in a movie we have one to several actors who play in. The ord attribute precise the rank of the actor in the movie. The couple (actorid, movieid) is a key for the table. actorid is a foreign key on ACTORS and movie id is a foreign key on MOVIES. A director is identified by an id (integer, key of the table) and a name 2. Questions to answer in Relational Algebra (algebraic trees) 2.1 Give the movies list (id, title and yr) ordered by title. 2.2 Give the list of movies having score greater or equal to 9. 2.3 Who are the main actors (ord equal to one) of movies released in 2000 ? We want id and name ordered by name. 2.4 Do the cartesian product between MOVIES and CASTINGS. 2.5 Give the id of movies released before 1930 or having actor's id 12 in their casting. 2.6 Give the names of stars (actors with ord equal to one) of the movie having id 11, in alphabetical order. 2.7 Give the names of directors of movies released before 1970 and having 'the' in their title. 2.8 Give the id and title of movies having no actors in their casting