【发布时间】:2023-04-07 21:30:02
【问题描述】:
如果我使用,我明白
class Fund{
private Set<FundClass> fundClasses = new LinkedHashSet<FundClass>();
@org.hibernate.annotations.OrderBy(clause="order asc")
public Set<FundClass> getFundClasses() {
return fundClasses;
}
}
然后我的 FundClasses 将是有序的,因为 hibernate 在幕后使用linkedHashset。同时,如果我想在 HQL 中使用 order by 子句,例如
from fund f inner join fetch f.fundClass fc order by fc.name
虽然 sql 按我想要的顺序返回记录,但是当我迭代它时,集合不是,即使我将它定义为linkedHashset。我有几个疑问,fundclass 需要按不同的顺序排列。有时按名称,有时按顺序和其他一些属性,我希望我可以在数据库中而不是在内存中进行排序。我该怎么做?
@Entity
@Table(name="GP")
public class GP {
private Integer id;
private String name;
private List<P> ps;
@Id
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(mappedBy="gp")
public List<P> getPs() {
return ps;
}
public void setPs(List<P> ps) {
this.ps = ps;
}
}
@Entity
@Table(name="P")
public class P {
private Integer id;
private String name;
private GP gp;
private List<C> cs;
@Id
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToOne
public GP getGp() {
return gp;
}
public void setGp(GP gp) {
this.gp = gp;
}
@OneToMany(mappedBy="p")
public List<C> getCs() {
return cs;
}
public void setCs(List<C> cs) {
this.cs = cs;
}
}
@Entity
@Table(name="C")
public class C {
private Integer id;
private String name;
private P p;
@Id
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToOne
public P getP() {
return p;
}
public void setP(P p) {
this.p = p;
}
}
我运行的查询
sessionFactory.getCurrentSession().createQuery("select gp from GP gp inner join fetch gp.ps p inner join fetch p.cs c where c.age< 5 and gp.name like 'john%'").list();
【问题讨论】:
标签: hibernate