CREATE TABLE principals (
      id INTEGER PRIMARY KEY ASC,
      uri TEXT,
      email TEXT,
      displayname TEXT,
      vcardurl TEXT,
      UNIQUE(uri)
  );
  
  CREATE TABLE groupmembers (
      id INTEGER PRIMARY KEY ASC,
      principal_id INTEGER,
      member_id INTEGER,
      UNIQUE(principal_id, member_id)
  );
  
  
  INSERT INTO principals (uri,email,displayname) VALUES ('principals/admin', 'admin@example.org','Administrator');
  INSERT INTO principals (uri,email,displayname) VALUES ('principals/admin/calendar-proxy-read', null, null);
  INSERT INTO principals (uri,email,displayname) VALUES ('principals/admin/calendar-proxy-write', null, null);