休眠@ManyToOne

Question

It`s possible to create one map with hibernate @ManyToOne just like this:

public class IndicadorAtos {
    @JsonIgnore
    @Id
    @Column(name="cod_ato_praticado")
    private Integer codAtoPraticado;
    @Column(name="descricao_ato")
    private String ato;


    @JoinColumn(name = "cod_ato", referencedColumnName = "cod_ato")
    @ManyToOne
    @Fetch(FetchMode.SUBSELECT)
    private Atos atos;

}

But in some cases I dont have association or in my table IndicadorAtos have one code, that don`t existis in table Atos

this is my tables:

create table IndicadorAtos (
  codAtoPraticado integer primary key,
  ato varchar(250), 
  cod_ato integer
);

create table Atos(
  cod_ato integer primary key.
  name varchar(250)
)

I try to create this join:

Select t FROM IndicadorAtos t , Atos a where t.cod_ato = a.cod_ato, but I need to return all records from my IndicadorAtos, and with this select he only return all itens that have one item in Atos.

tks

Answer 1

It`s possible to create one map with hibernate @ManyToOne

Yes; it is called unidirectional relationship.

If I understood your question properly, you want to select all entries from IndicadorAtos with possibly associated entries from Atos . You can achieve this by using left join as follows:

SELECT t FROM IndicadorAtos t LEFT JOIN t.atos at

provided that you have an entity Atos defined like:

@Entity
public class Atos {
    @Id @GeneratedValue
    private int cod_ato;

    private String name;

    // getters and setters
}