程序代码：

drop table user;
create table user(
ID int(10) primary key auto_increment,
password varchar(10),
user_name varchar(10),
actor_id int(10)
);

insert into user values(1,'joe','joe',1);
insert into user values(2,'kan','kan',2);
insert into user values(3,'gern','gern',2);
insert into user values(4,'jone','jone',3);
insert into user values(5,'jack','jack',3);
insert into user values(6,'jake','jake',3);
ALTER TABLE user ADD CONSTRAINT fk_actor 
FOREIGN KEY (actor_id) 
REFERENCES actor(id);
drop table actor;
create table actor(
ID int(10) primary key auto_increment,
actor_name varchar(10)
);
insert into actor values(1,'sup_user');
insert into actor values(2,'gen_user');
insert into actor values(3,'sim_user');
drop table droit;
create table droit(
ID int(10) primary key auto_increment,
droit_name varchar(10),
actor_id int(10)
);
ALTER TABLE user ADD CONSTRAINT fk_driot 
FOREIGN KEY (actor_id) 
REFERENCES actor(id);
insert into droit values(1,'I',1);
insert into droit values(2,'D',1);
insert into droit values(3,'M',1);
insert into droit values(4,'S',1);
insert into droit values(5,'I',2);
insert into droit values(6,'M',2);
insert into droit values(7,'S',2);
insert into droit values(8,'S',3);