英文:
JPA @OrderBy with Hibernate
问题
I'm here to help with the translation. Here's the translated code part:
我正在使用Hibernate，并想要使用`@OrderBy`来对`resultSet`进行排序：public class TopLevelEntity extends Entity {@OneToMany(mappedBy = "topLevelEntity", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<TopLevelEntityTranslation> translations;//other fields}public class NextLevelEntity extends Entity {@OneToMany(mappedBy = "nextLevelEntity", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<NextLevelEntityTranslation> translations;@Columnprivate Long number;//other fields}public class TopLevelEntityTranslation extends Entity {@ManyToOne@JoinColumn(name = "TOP_LVL_ENTITY_ID")private TopLevelEntity topLevelEntity;@OrderBy("nextLevelEntity.number")@OneToMany(mappedBy = "topLevelEntityTranslation", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<NextLevelEntityTranslation> nextLevelEntityTranslations;//other fields}public class NextLevelEntityTranslation extends Entity {@ManyToOne@JoinColumn(name = "TOP_LVL_ENTITY_TR_ID")private TopLevelEntityTranslation topLevelEntityTranslation;@ManyToOne@JoinColumn(name = "NEXT_LVL_ENTITY_ID")private NextLevelEntity nextLevelEntity;//other fields}
If you have any more questions or need further assistance, please let me know.
英文:
Im using hibernate and want to use @OrderBy to order a resultSet:
public class TopLevelEntity extends Entity {@OneToMany(mappedBy = "topLevelEntity", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<TopLevelEntityTranslation> translations;//other fields}public class NextLevelEntity extends Entity {@OneToMany(mappedBy = "nextLevelEntity", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<NextLevelEntityTranslation> translations;@Columnprivate Long number;//other fields}public class TopLevelEntityTranslation extends Entity {@ManyToOne@JoinColumn(name = "TOP_LVL_ENTITY_ID")private TopLevelEntity topLevelEntity;@OrderBy("nextLevelEntity.number")@OneToMany(mappedBy = "topLevelEntityTranslation", fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)private Set<NextLevelEntityTranslation> nextLevelEntityTranslations;//other fields}public class NextLevelEntityTranslation extends Entity {@ManyToOne@JoinColumn(name = "TOP_LVL_ENTITY_TR_ID")private TopLevelEntityTranslation topLevelEntityTranslation;@ManyToOne@JoinColumn(name = "NEXT_LVL_ENTITY_ID")private NextLevelEntity nextLevelEntity;//other fields}
I have an entity hierarchy like shown above. But @OrderBy annotation(no the annotation ofc, but the statement generated by hibernate) throws an exception. Exception main part:
> missing FROM-clause entry for table "nextLevelEntity"
There are few examples of using jpa @OrderBy but pattern of those that I found is the same with mine.
Read that @OrderBy doesn't work well with Hibernate's JPA implementation. But the question was asked 7 years ago. Is it true or i have a mistake in my code?
答案1
得分: 3
根据@OrderBy的文档：
点号（"."）符号用于引用嵌入属性中的属性。与点号符号一起使用的每个标识符的值都是相应嵌入字段或属性的名称。
示例：
@Entitypublic class Person {...@ElementCollection@OrderBy("zipcode.zip, zipcode.plusFour")public Set<Address> getResidences() {...};...}@Embeddablepublic class Address {protected String street;protected String city;protected String state;@Embeddedprotected Zipcode zipcode;}@Embeddablepublic class Zipcode {protected String zip;protected String plusFour;}
所以，对于您的情况，您不能使用它。
英文:
Actually, according to the documentation for the @OrderBy:
> The dot (".") notation is used to refer to an attribute within an embedded attribute. The value of each identifier used with the dot notation is the name of the respective embedded field or property.
Example:
@Entitypublic class Person {...@ElementCollection@OrderBy("zipcode.zip, zipcode.plusFour")public Set<Address> getResidences() {...};...}@Embeddablepublic class Address {protected String street;protected String city;protected String state;@Embeddedprotected Zipcode zipcode;}@Embeddablepublic class Zipcode {protected String zip;protected String plusFour;}
So, you can not use it for your case.
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