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我面临的情况与this question一样,没有有用的答案。如何避免Hibernate使用OneToMany生成两个查询更新?
当我将一个新元素添加到我的一对多关系的很多部分时,Hibernate会生成两个查询,一个用于插入,另一个用于将外键更新为父项。
为什么需要第二个查询?插入中是否设置了父代的ID? 有什么办法可以避免这种情况?
Hibernate:
/* insert mydomain.LanguageKnowledge */
insert
into
languageKnowledge
(language_fk, level_fk, personId_fk)
values
(?, ?, ?)
Hibernate:
/* create one-to-many row mydomain.Person.offeredLanguages */
update
languageKnowledge
set
personId_fk=?
where
id=?
public class LanguageKnowledge {
@Id
@GeneratedValue(strategy = IDENTITY)
private Integer id;
@Enumerated(STRING)
@Column(name = "language_fk")
private LanguageIso639_3 language;
@Enumerated(STRING)
@Column(name = "level_fk")
private LanguageLevel level;
protected LanguageKnowledge() {
}
}
public class Person {
@Id
@GeneratedValue(strategy = IDENTITY)
private Integer id;
@OneToMany(fetch = EAGER, cascade = {ALL}, orphanRemoval = true)
@JoinColumn(name = "personId_fk", referencedColumnName = "id", nullable = false)
private final Set<LanguageKnowledge> offeredLanguages = new HashSet<>();
public Person(Set<LanguageKnowledge> offeredLanguages) {
addOfferedLanguages(offeredLanguages);
}
protected Person() {
}
public void addOfferedLanguages(Set<LanguageKnowledge> offeredLanguages) {
this.offeredLanguages.addAll(offeredLanguages);
}
public void removeOfferedLanguages(Set<LanguageKnowledge> offeredLanguagesToRemove) {
this.offeredLanguages.removeAll(offeredLanguagesToRemove);
}
}
你想避免哪个查询?这两个看起来很有用.... –
@JordiCastilla第二个,更新。编辑我的问题。 – mark951131b