save an object with childs in Hibernate/JPA - @OneToMany

Question

In Hibernate I want to save an object that has a child.In parent Object I have Set of other classes that are child. The parent hase a @OneToMany relationship with the child.

parent :

@Entity
public class TalentIdentitySetting {

 @OneToMany(fetch = FetchType.LAZY, mappedBy = "setting", cascade = CascadeType.ALL, orphanRemoval = true)
 private Set<TalentIdentitySettingPower> settingPowers;

 @OneToMany(fetch = FetchType.LAZY, mappedBy = "setting", cascade = CascadeType.ALL, orphanRemoval = true)
 private Set<TalentIdentitySettingSpeciality> settingSpecialities;

}

child :

@Entity
public class TalentIdentitySettingPower {

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "IDENTITY_SETTING_ID", nullable = false)
 private TalentIdentitySetting setting;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "POWER_ID", nullable = false)
 private BasePower power;

}

how I can save parent and child together in one transaction. This is my problem; When the child wants to be saved the parent has not been saved yet and say parent key not found. In fact, hibernate should save the parent first and then the child.

I used PERSIST cascade but it still didn't work.

please help me.

How you are setting and saving it? please share some code? – SSK Sep 02 '20 at 12:39 — SSK, Sep 02 '20 at 12:39

score 0 · Accepted Answer · answered Sep 02 '20 at 11:33

I believe your JPA Annotation is correct, this is likely that your TalentIdentitySettingPower.setting is not being set before it saved

Let say if you have the following code

        TalentIdentitySetting setting = new TalentIdentitySetting();
        HashSet<TalentIdentitySettingPower> powers = new HashSet<>();
        powers.add(new TalentIdentitySettingPower());
        powers.add(new TalentIdentitySettingPower());
        powers.add(new TalentIdentitySettingPower());
        setting.setSettingPowers(powers);
        repository.save(setting);

This will fail and complain about null-value issue

If you add a constructor method in TalentIdentitySettingPower

    public TalentIdentitySettingPower(TalentIdentitySetting setting) {
        this.setting = setting;
    }

and

        TalentIdentitySetting setting = new TalentIdentitySetting();
        HashSet<TalentIdentitySettingPower> powers = new HashSet<>();
        powers.add(new TalentIdentitySettingPower(setting));
        powers.add(new TalentIdentitySettingPower(setting));
        powers.add(new TalentIdentitySettingPower(setting));
        setting.setSettingPowers(powers);
        repository.save(setting);

This will successfully save the value into database.

Base on your sample, I create an application https://github.com/hepoiko/stack-63703687

I would not say this should be handled by Hibernate. Hibernate handles the relationship between object to database. — Chun, Sep 06 '20 at 07:35

save an object with childs in Hibernate/JPA - @OneToMany

1 Answers1