请帮助创建查询!我必须通过公共父对象按 categoryId 选择所有标签。
我有下一个:
@Table(name="ADVERT")
@Entity(name="Advert")
public class JpaAdvert implements Advert{
@Id
@GeneratedValue
private long id;
@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name="category_id", referencedColumnName="id")
private JpaCategory category = new JpaCategory();
@ManyToMany(fetch=FetchType.EAGER, cascade={CascadeType.PERSIST, CascadeType.MERGE})
@JoinTable(name="ADVERT_TAGS", joinColumns=@JoinColumn(name="advert_id",referencedColumnName="id"), inverseJoinColumns=@JoinColumn(name="tag_id", referencedColumnName="id"))
private Set<JpaTag> tags = new HashSet<JpaTag>();
...
标签对象:
@Entity(name="Tag")
@Table(name="TAG")
public class JpaTag implements Tag {
@Id
@GeneratedValue
private long id;
private String name;
private long weight=1;
private String locale;
....
和类别对象:
@Table(name="CATEGORY")
@Entity(name="Category")
public class JpaCategory implements Category {
@Id
@GeneratedValue
private long id;
@Column(name="category_name")
private String categoryName;
.....
所以我需要按类别 ID 选择属于特定类别的所有标签。怎么做对我来说有点复杂!
请帮助任何人!