How do I set up a column to be composed in Mysql with Hibernate (Java)?

Question

I’m doing a CRUD and in creating my model I’ve reached a point where I can’t get out. I have a table "Plan" and each plan can have several "Modalities", as well as several "Extras", but I do not know how to create these two compound fields using Hibernate.

I was creating the two fields as a "Modality" and "Extra" Object, but I noticed that only 1 Modality and 1 Extra would be registered in the table "Plan", and if the Plan were more than one modality, the second would not be in the table "Plan".

public class Plano extends GenericDomain{

@Column(length = 50, nullable = false)
private String nome;

@Column(nullable = false)
private Short quanModalidade;

@Column(nullable = false)
private Short quanExtra;

@Column(nullable = false)
private String duracao; //Mensal,Semestre ou Anual

@Column(nullable = false, precision = 6, scale = 2)
private BigDecimal valor;

@Column(nullable = false)
private Short adquirentes;

@JoinColumn(nullable = false)
@ManyToOne
private Extra extra;

@JoinColumn(nullable = false)
@ManyToOne
private Modalidade modalidade;

public String getNome() {
    return nome;
}

public void setNome(String nome) {
    this.nome = nome;
}

public Short getQuanModalidade() {
    return quanModalidade;
}

public void setQuanModalidade(Short quanModalidade) {
    this.quanModalidade = quanModalidade;
}

public Short getQuanExtra() {
    return quanExtra;
}

public void setQuanExtra(Short quanExtra) {
    this.quanExtra = quanExtra;
}

public String getDuracao() {
    return duracao;
}

public void setDuracao(String duracao) {
    this.duracao = duracao;
}

public BigDecimal getValor() {
    return valor;
}

public void setValor(BigDecimal valor) {
    this.valor = valor;
}

public Short getAdquirentes() {
    return adquirentes;
}

public void setAdquirentes(Short adquirentes) {
    this.adquirentes = adquirentes;
}

public Extra getExtra() {
    return extra;
}

public void setExtra(Extra extra) {
    this.extra = extra;
}

public Modalidade getModalidade() {
    return modalidade;
}

public void setModalidade(Modalidade modalidade) {
    this.modalidade = modalidade;
 }
}

Answer 1

I believe that its mapping is wrong, if a "plan" can have several "modalities" and "extras" should use the mapping @oneToMany in the "plane" where the mode and the extra would store the id of the reference plan in the simple example sql table

If it is @Manytomany, that is, The same "plan" for various "modality" and the same "modality" for various "plans" must be created an intermediate table to record this relation.

So there has to be an intermediate table for each relationship (Plano_modality) and (Plano_extra) simple example:

Note: Tips from @Manytomany using unidirectional or bidirectional

As an example for @Manytomany following the idea of this Link: https://www.baeldung.com/hibernate-many-to-many Would look like this:

@Entity
@Table(name = "Plano")
public class Plano { 
    // ...

    @ManyToMany(cascade = { CascadeType.ALL })
    @JoinTable(
        name = "Plano_Modalidade", 
        joinColumns = { @JoinColumn(name = "id_plano") }, 
        inverseJoinColumns = { @JoinColumn(name = "id_modalidade") }
    )
    List<Modalidade> modalidades;

    // getters/setters
}

@Entity
@Table(name = "Modalidade")
public class Modalidade {    
    // ...  

    @ManyToMany(mappedBy = "modalidades")
    private List<Plano> Planos;

    // getters/setters   
}