@Entity
@SQLDelete(sql = "update Comment set deleted = 1 where id = ?")
@Where(clause = "deleted = 0")
public class Comment {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @ManyToOne(cascade = CascadeType.MERGE, fetch = FetchType.EAGER)
    @JoinColumn(name = "authorId")
    private User author;

    private String content;
    private Date createdAt;
    private boolean deleted;
    private Date deletedAt;

    //constructors, getters & setters...
}