CODEWITHSUNDEEP
hibernatejpa
Martinas Maria
Martinas Maria

Reputation: 119

JPA Hibernate - changing the primary key of an persisted object

I am trying to change the id of an persisted object .I am using JPA with Hibernate and MySQL. The error I get when executing my code is : org.hibernate.HibernateException: identifier of an instance of com.tutorial.jpa.certification.listing5_18.AA was altered from 2 to 99

I couldn't find an answer to this problem so I would appreciate your help here.The code is:

    EntityManagerFactory emf=Persistence.createEntityManagerFactory("Tutorial");
    EntityManager em=emf.createEntityManager();     
    AA aa=em.find(AA.class, 2);

    em.getTransaction().begin();
    aa.setId(99);
    em.merge(aa);
    em.getTransaction().commit();

Upvotes: 7

Views: 17534

Answers (1)

Eugen
Eugen

Reputation: 8783

You should never modify the primary key of a an entity - this define the identify of the object and it makes no sense to change it.

If you really do need that - you'd be better of deleting the entity and creating a new one which just copies the old one but with a new primary key. This way, if you have any constraints - such as foreign keys pointing to the old identifier - you'll know about it.

Also check out the "Identity and Sequencing" section here.

Hope this helps.

Upvotes: 18

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