text: CREATE TABLE Idol (
  id INTEGER PRIMARY KEY,
  url TEXT UNIQUE,
  name TEXT);
  
  -- 'Group' is a reserved name
  CREATE TABLE Groups (
  id INTEGER PRIMARY KEY,
  name TEXT UNIQUE);
  
  CREATE TABLE IdolGroups (
  id_groups INTEGER,
  id_idol INTEGER,
  FOREIGN KEY (id_groups) REFERENCES Groups(id),
  FOREIGN KEY (id_idol) REFERENCES Idol(id),
  PRIMARY KEY (id_groups, id_idol));
  
  CREATE TABLE Image (
  url TEXT PRIMARY KEY,
  id_idol INTEGER,
  FOREIGN KEY (id_idol) REFERENCES Idol(id));