Error on em.getTransaction().commit(); using the JPA @Embeddable annotation

Question

I have some problems with @Embeddable in JAVA JPA. I have an entity class named "Author":

@Entity

    @Table(name = "author")
    @XmlRootElement
    @NamedQueries({
        @NamedQuery(name = "Author.findAll", query = "SELECT a FROM Author a"),
       ...})


    public class Author implements Serializable {
        private static final long serialVersionUID = 1L;
        @Id
        @Basic(optional = false)
        @Column(name = "aID")
        private Integer aID;
        @Column(name = "aName")
        private String aName;
        @Column(name = "aSurname")
        private String aSurname;
        @Column(name = "aPhone")
        private Integer aPhone;


        @Embedded 
        @AttributeOverrides({

         @AttributeOverride(name="city",column=@Column(name="Address")),
         @AttributeOverride(name="street",column=@Column(table="Address")),
         @AttributeOverride(name="number",column=@Column(table="Address"))
         }) private Address address;

    // set and get methods.
    }

Also I have an Embeddable class named "Address":

@Embeddable
    @Table(name = "Address")
    @XmlRootElement
    public class Address implements Serializable 
    {
       private static final long serialVersionUID=1L;
        @Column(name="city")
        private String city;
        @Column(name="street")
        private String street;
        @Column(name="number")
        private int number;

    // get and set methods.
}

In my main class I want to insert this values to the database. (I use mySQL) But I am getting an error on this line: em.getTransaction.commit();

    public class CreateAuthor extends javax.swing.JFrame {

        private static final String PERSISTENCE_UNIT_NAME = "Project";
        private static EntityManagerFactory emf;

        public void CreateAuthor() {
            initComponents();
        }


        private void ekleButtonActionPerformed(java.awt.event.ActionEvent evt) {                                           
            emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
            EntityManager em = emf.createEntityManager();


            em.getTransaction().begin();


            Author author = new Author();
            author.setAID(3);
            author.setAName("Sheldon");
            author.setASurname("Smith");
            author.setAPhone(768987);
            Address adr = new Address();



             adr.setCity("Paris");
             adr.setStreet("cinar");
             adr.setNumber(12);
             author.setAddress(adr);



            em.persist(author);

            em.getTransaction().commit();  /// error occured

            em.close();       

    }
}

On my database side, I have Author table (aID(pk),aName,aSurname,aPhone)

Address Table (city,street,number)

Do you have any idea why an error is occured?

Answer 1

The goal of Embeddable is to have fields of an object (Address) stored in the same table as the entity's table (Author -> author).

If you want to save them in another table, than Address should be an entity on its own, and there should be a OneToOne or ManyToOne association between Author and Address. The mapping, as is, don't make any sense.