Music categorization database

Recently I've tried to teach myself basic things about MySQL databases, however I received some help on Stack Overflow with creating a good database structure trying to avoid redundancy as much as possible.

I finally came up with the database structure below and would like to know if that's the way to go and if not, what you would improve/change to it.

```
CREATE TABLE artists (
artist_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
artist_name varchar(100) UNIQUE,
artist_aka varchar(255) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE labels (
label_id SMALLINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
label_name varchar(100) UNIQUE,
label_aka varchar(255) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE producers (
producer_id SMALLINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
producer_forename varchar(100),
producer_nickname varchar(100) UNIQUE,
producer_lastname varchar(100)
) ENGINE = 'InnoDB';

CREATE TABLE years (
year_id TINYINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
year_value varchar(4) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE genres (
genre_id TINYINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
genre_name varchar(10) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE flags (
flag_id TINYINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
flag_name varchar(12) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE tags (
tag_id SMALLINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
tag_name varchar(16) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE sources (
source_id TINYINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
source_name varchar(30) UNIQUE
) ENGINE = 'InnoDB';

CREATE TABLE riddims (
riddim_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
riddim_name varchar(40) UNIQUE,
riddim_aka varchar(255) UNIQUE,
genre_fk TINYINT,
youtube varchar(11) UNIQUE,
image varchar(11) UNIQUE,
FOREIGN KEY (genre_fk) REFERENCES genres(genre_id) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE = 'InnoDB';

CREATE TABLE tunes (
tune_id INT AUTO_INCREMENT

Just a couple of suggestions.

First, artists and producers are both persons and a person can be both an artist and a producer (even on their own songs).

Second, more than one persons can work together on a song, but in lots of different roles (backup musician, backup singer, "featuring", "uncredited", or as a member of a groups). So performers and roles would probably look something like:

CREATE TABLE roles (
    role_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    description varchar(100) not null
) ENGINE = 'INNODB';

CREATE TABLE performers (
    performer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    tune_fk INT NOT NULL,
    person_fk INT NOT NULL,
    role_fk INT NOT NULL,
    FOREIGN KEY (tune_fk) REFERENCES tunes(tune_id) ON DELETE SET NULL ON UPDATE CASCADE,
    FOREIGN KEY (person_fk) REFERENCES persons(person_id) ON DELETE SET NULL ON UPDATE CASCADE,
    FOREIGN KEY (role_fk) REFERENCES roles(role_id) ON DELETE SET NULL ON UPDATE CASCADE,
) ENGINE = 'InnoDB';

StackExchange Code Review Q#15678, answer score: 4