@Entity
@Table(name = "article")
@SecondaryTable(
    name = "article_content",
    pkJoinColumns = @PrimaryKeyJoinColumn(name = "id")
)
public class Article {
    @Id @GeneratedValue
    private Long id;
    private String title;
    
    @AttributeOverrides({
        @AttributeOverride(name = "content", column = @Column(table = "article_content")),
        @AttributeOverride(name = "contentType", column = @Column(table = "article_content"))
    })
    private ArticleContent content;
}