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請幫忙建立一個查詢! 我必須通過共同父對象選擇所有標籤類別標識。JPA QueryBuilder
我旁邊:
@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", [email protected](name="advert_id",referencedColumnName="id"), [email protected](name="tag_id", referencedColumnName="id"))
private Set<JpaTag> tags = new HashSet<JpaTag>();
...
標籤對象:
@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;
....
和類別對象:
@Table(name="CATEGORY")
@Entity(name="Category")
public class JpaCategory implements Category {
@Id
@GeneratedValue
private long id;
@Column(name="category_name")
private String categoryName;
.....
所以我需要選擇屬於特定類別的所有標籤按類別ID。對我來說,如何做到這一點有點複雜!
請幫助任何人!