Who generates foreign key? hibernate or database?

Hibernate ORM
1

I’ve created a table like this:

CREATE TABLE employee (
   id int(11) NOT NULL AUTO_INCREMENT,
   first_name varchar(45) DEFAULT NULL,
   last_name varchar(45) DEFAULT NULL,
   PRIMARY KEY(id)
)

as You see, I’ve used: AUTO_INCREMENT

Then Why should I use @GeneratedValue in my Entity Class while I’ve specified auto increment in the definition of table to make it self-incremental?

My Entitiy Class:

@Entity
@Table(name = "employee")
public class Employee{

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;
.
.
.
}

if database is going to generate primary key, then why should I specify the way of generation of primary key in entity class?

who generates foreign key? hibernate or database?