hibernate cascade to save parent and child

Question

i have 2 class. Parent and child. as follows:

@Entity
@Table(name = "parent")
public class Parent implements Serializable {
    private String name;
    private List<Child> childs;

    @OneToMany(mappedBy="parent")
    @Cascade({CascadeType.SAVE_UPDATE, CascadeType.DELETE})
    public List<Child> getChilds() {
        return childs;
    }
    @Id
    @Column(name="parent_name")
    public String getName() {
        return name;
    }    

}

>

@Entity
@Table(name = "child")
public class Child implements Serializable {

    @JoinColumn(name="parent_name")
    private Parent parent;

    public Parent getParent() {
        return parent;
    }

    public void setParent(Parent parent) {
        this.parent = parent;
    }

}

when i use session.save(parent) it saves parent and child in the database but the column of parent identifier in child table will remain null. so what is the problem?

how are u generating PK ID in Parent? I am not seeing it in code — sanbhat, Jun 25 '13 at 11:04
@OneToMany(mappedBy="parent") is saying hibernate to automatically create parent id in child — abozar, Jun 25 '13 at 11:54

score 0 · Answer 1 · edited Jun 26 '13 at 12:09

0

try this on child Entity:

 @ManyToOne(targetEntity = Parent.class)

 @JoinColumn(name = "parent", nullable = false)

edited Jun 26 '13 at 12:09

RAS

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answered Jun 25 '13 at 12:13

Jorge Iten Jr

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nothing changed. just an error about sql constraint violation : org.hibernate.exception.ConstraintViolationException: Column 'parent' cannot be null – abozar Jun 25 '13 at 15:21
1

I don't think hibernate will refresh the child when saving the parent. You could do it by yourself, like this: public void addChild(Child child) { this.childs.add(child); child.setParent(this); } – Jorge Iten Jr Jun 25 '13 at 17:28
when i commit the transaction, hibernate will send query to fill columns such this(parent column in child table). so i think it is because i declared parent by myself in child and hibernate will no longer has the responsibility to fill it when commit. any way i will try fill it by my own if not any other opinion exist. – abozar Jun 26 '13 at 04:41

score 0 · Answer 2 · edited Jun 26 '13 at 16:21

0

If I declare OneToMany as Unidirectional, it works well.

edited Jun 26 '13 at 16:21

Ry-

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answered Jun 26 '13 at 11:39

abozar

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hibernate cascade to save parent and child

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