How to solve (Java + Spring + JPA + Hibernate Mappings) relationships

Question

I have read many topics about mapping with JPA + Hibernate, but after trying several things I can not get the expected result.

I have declared all my unidirectional relationships since I do not see the need to bidirect them

My objects to map are: Client has a Country and a list of addresses.

@Table(name = "Client")
@Entity
public class Client
{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    private Long id;

    @OneToOne(cascade = { CascadeType.MERGE, CascadeType.PERSIST })
    @JoinColumn(name="country_id", unique = false, /*nullable = false,*/ insertable = true, updatable = false, foreignKey = @ForeignKey(name = "country_fk0"))
    private Country country;

    @OneToMany(cascade = { CascadeType.PERSIST }, orphanRemoval = true)
    @JoinColumn(name = "address_id",/* nullable = false,*/ foreignKey = @ForeignKey(name = "address_fk0"))
    private List<Address> address;

//GETTERS / SETTERS
}

then I will evaluate the client and save it in a new ClientProcessed table, which will reference the Addresses and Country objects stored in my Client Object.

@Table(name = "ProcessedClient")
@Entity
public class ProcessedClient
{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    private Long id;

    @OneToOne(cascade = { CascadeType.MERGE, CascadeType.PERSIST })
    @JoinColumn(name="client_evaluation_id", unique = false, /*nullable = false,*/ insertable = true, updatable = false, foreignKey = @ForeignKey(name = "evaluation_fk0"))
    private ClientEvaluation evaluation;

    @OneToOne(cascade = { CascadeType.MERGE })
    @JoinColumn(name="country_id", unique = false, /*nullable = false,*/, foreignKey = @ForeignKey(name = "country_fk1"))
    private Country country;

    @OneToMany(cascade = { CascadeType.MERGE}, orphanRemoval = true)
    @JoinColumn(name = "address_id",/* nullable = false,*/ foreignKey = @ForeignKey(name = "address_fk2"))
    private List<Address> addresses;

//GETTERS / SETTERS
}

So then when i do that:

Country country = new Country();
country.setId(1l); // (DB ID)

// I do the same with addresses

ProcessedClient processedClient = new ProcessedClient();
processedClient.setAddresses(addresses);
processedClient.setCountry(country);

this.getDao().save(processedClient);

Result:

org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing

Thx

Answer 1

From documentation:

Hibernate defines and supports the following object states:

• Transient - an object is transient if it has just been instantiated using the new operator, and it is not associated with a Hibernate Session . ...
• Persistent - a persistent instance has a representation in the database and an identifier value.

You should load country from database by id and then set it to ProcessedClient.