I have a Parent table that should point to some Childs, Here are my codes:
Parent :
public class Parent
{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
@OneToMany(mappedBy = "parent", cascade = CascadeType.ALL)
private List<Child> childs;
public List<Child> getChilds()
{
return this.childs;
}
public void setChilds(List<Child> childs)
{
this.childs = childs;
}
public void setId(Integer id)
{
this.id = id;
}
public Integer getId()
{
return this.id;
}
}
Child :
public class Child
{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
@ManyToOne
@JoinColumn(name = "parent_id")
private Parent parent;
public void setParent(Parent parent)
{
this.parent = parent;
}
public Parent getParent()
{
return this.parent;
}
public void setId(Integer id)
{
this.id = id;
}
public Integer getId()
{
return this.id;
}
}
Child table should store parent_id as foreign key, but without setting child.setParent(parent)
this column is always null.
I don't want to call child.setParent(parent)
because it will cause performance issue because i should create iterate.
Child
是关系的所有者,因此您必须调用child.setParent(parent)
才能正确设置关系。
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