sql 3NF Normalization

Question

is this in 3NF ?

create table movies( 
  id numeric primary key not null default autoincrement,
  name varchar(50) not null, 
  release-date Date, 
  price numeric, 
  rating numeric,
  length numeric,
  description varchar(1500)
);

create table movies( 
  id numeric primary key, 
  name varchar(20) 
);

create table genre(
  name varchar(20) primary key
);

create table directors(
  id numeric primary key not null default autoincrement, 
  first-name varchar(32) not null, 
  last-name varchar(32) not null, 
  gender varchar(8), 
  dob Date, 
  biography varchar(1000)
);

create table movie-Star(
  id numeric primary key not null default autoincrement, 
  first-name varchar(20) not null, 
  last-name varchar(20) not null,
  gender varchar(8), 
  dob Date, 
  hometown varchar(20)
);

create table movies-cast(
  movie-id numeric references movies(id), 
  actor-id numeric references movie-Star(id), 
  role varchar(32), 
  primary key (movie-id, actor-id)
);

Create table Studio( 
  studio-id numeric references directors(id)
  Directer-name varchar(20) not null
  name varchar(20) primary key
);

create table directors(
  id numeric primary key not null default autoincrement, 
  first-name varchar(32) not null, 
  last-name varchar(32) not null, 
  gender varchar(8), 
  dob Date, 
  biography varchar(1000)
);

Answer 1

It looks pretty well structured. I don't see any normalization problems. However:

• Movies and Directors tables are created twice.
• Genre table is not used for anything (presumably should be in movies).
• Same with Studios.
• Current arrangement allows only one director per studio. This should probably be A) one studio per director (add studio_id column to directors) or more likely B) many-to-many relationship between studio and director (add new studio_directors table).
• Current arrangement does not associate Director with Movie.
• You might consider combining Director and Movie-Start into one table called Talent. You have data duplication in which a star is also a director. This is the biggest normalization issue with your design.

Answer 2

if all can not be duplicated again then it is included 3NF. make sure there are not duplicate data again

Answer 3

It has e PK, so it's in 1NF. It's PK is not composite, so it's in 2NF. All the columns are dependent on nothing but the key, so it's in 3NF. There no keys other than PK, so it's in BCNF.