@Column(unique=true) does not seem to work

Even though I set the attribute to be @Column(unique=true), I still insert a duplicate entry.

@Entity
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(unique=true )
    private String name;

    ...
}

I set the name using regular EL in JSF. I did not create table using JPA