休眠条件返回具有一对一子记录的父记录不为null? [英] Hibernate Criteria Return parent record that have one-to-one child record not null?
问题描述
我有这样的一对一关系
父母
@JsonAutoDetect
@Entity
@Table(name = "Parent")
public class Parent{
private Integer id;
private Child child;
@Id
@GeneratedValue(strategy= GenerationType.AUTO)
@Column (name="idparent")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "parent")
@JoinColumn(name="idchild", nullable=true)
public Child getChild() {
return child;
}
public void setChild(Child child) {
child.setParent(this);
this.child = child;
}
}
和孩子
@JsonAutoDetect
@Entity
@Table(name="Child")
public class Child{
private Integer id;
private Parent parent;
@Id
@GeneratedValue(generator = "foreign")
@GenericGenerator(name = "foreign", strategy = "foreign", parameters = { @Parameter(name = "property", value = "parent") })
@Column (name = "idchild")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@OneToOne(fetch = FetchType.LAZY, optional = true)
@Cascade({ org.hibernate.annotations.CascadeType.SAVE_UPDATE })
@PrimaryKeyJoinColumn
@JsonIgnore
public Parent getParent() {
return parent;
}
public void setParent(Parent parent) {
this.parent= parent;
}
}
我想创建返回具有孩子isNotNull的父母的条件,我尝试过这样的想法
I want to create criteria that return the parent that have child isNotNull, i tryed somme think like
Criteria criteria = session.createCriteria(Parent.class);
criteria.add(Restrictions.isNotNull("child"));
但是不行,请给我个榜样可以帮助我吗?谢谢
But not work, can you help me by giving somme example please ? Thanks
推荐答案
首先,映射错误.在父类中,您说的是该关联是由child.parent
映射的,而在您说该关联是使用名为id_child
的连接列进行映射之后.下定决心.要么由child.parent
属性映射,您都应删除@JoinColumn
.或者它是由JoinColumn映射的,您应该删除子级中的@PrimaryKeyJoinColumn
,并在子级实体中使用mappedBy="child"
.
First of all, the mapping is wrong. In the parent class, you're saying that the association is mapped by child.parent
, and immediately after you're saying that it's mapped using a join column named id_child
. Make up your mind. Either it's mapped by the child.parent
property, and you should remove the @JoinColumn
. Or it's mapped by the JoinColumn and you should remove the @PrimaryKeyJoinColumn
in the child, and use mappedBy="child"
in the Child entity.
现在,要使查询正常工作,无论映射是什么,您都应该简单地进行内部联接:
Now, to make your query work, whatever the mapping is, you should simply make an inner join:
Criteria criteria = session.createCriteria(Parent.class);
criteria.createAlias("child"); // inner join
由于联接是内部联接,因此它将仅选择具有非空子代的父母.
Since the join is an inner join, it will only select parents that have a non-null child.
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