text: CREATE TABLE countries (
      id INT PRIMARY KEY AUTO_INCREMENT,
      `name` VARCHAR(45) NOT NULL
  );
  
  CREATE TABLE towns (
      id INT PRIMARY KEY AUTO_INCREMENT,
      `name` VARCHAR(45) NOT NULL,
      country_id INT NOT NULL,
      CONSTRAINT fk_towns_countries FOREIGN KEY (country_id)
          REFERENCES countries (id)
  );
  
  CREATE TABLE stadiums (
      id INT PRIMARY KEY AUTO_INCREMENT,
      `name` VARCHAR(45) NOT NULL,
      capacity INT NOT NULL,
      town_id INT NOT NULL,
      CONSTRAINT fk_stadiums_towns FOREIGN KEY (town_id)
          REFERENCES towns (id)
  );
  
  CREATE TABLE teams (
      id INT PRIMARY KEY AUTO_INCREMENT,
      `name` VARCHAR(45) NOT NULL,
      established DATE NOT NULL,
      fan_base BIGINT NOT NULL DEFAULT 0,
      stadium_id INT NOT NULL,
      CONSTRAINT fk_teams_stadiums FOREIGN KEY (stadium_id)
          REFERENCES stadiums (id)
  );
  
  CREATE TABLE skills_data (
      id INT PRIMARY KEY AUTO_INCREMENT,
      dribbling INT DEFAULT 0,
      pace INT DEFAULT 0,
      passing INT DEFAULT 0,
      shooting INT DEFAULT 0,
      speed INT DEFAULT 0,
      strength INT DEFAULT 0
  );
  
  CREATE TABLE players (
      id INT PRIMARY KEY AUTO_INCREMENT,
      first_name VARCHAR(10) NOT NULL,
      last_name VARCHAR(20) NOT NULL,
      age INT NOT NULL DEFAULT 0,
      position CHAR(1) NOT NULL,
      salary DECIMAL(10 , 2 ) NOT NULL DEFAULT 0,
      hire_date DATETIME,
      skills_data_id INT NOT NULL,
      team_id INT,
      CONSTRAINT fk_players_teams FOREIGN KEY (team_id)
          REFERENCES teams (id),
      CONSTRAINT fk_players_skills FOREIGN KEY (skills_data_id)
          REFERENCES skills_data (id)
  );
  
  CREATE TABLE coaches (
      id INT PRIMARY KEY AUTO_INCREMENT,
      first_name VARCHAR(10) NOT NULL,
      last_name VARCHAR(20) NOT NULL,
      salary DECIMAL(10 , 2 ) NOT NULL DEFAULT 0,
      coach_level INT NOT NULL DEFAULT 0
  );
  
  CREATE TABLE players_coaches (
      player_id INT,
      coach_id INT,
      CONSTRAINT pk_players_coaches PRIMARY KEY (player_id , coach_id),
      CONSTRAINT fk_players FOREIGN KEY (player_id)
          REFERENCES players (id),
      CONSTRAINT fk_coaches FOREIGN KEY (coach_id)
          REFERENCES coaches (id)
  );