many-to-many

The many-to-many fields are defined by the tag <many-to-many> :

<entity name="Musicien">
    ...
    <many-to-many name="instruments" ref="Instrument"/>
</entity>

<entity name="Instrument">
    ...
</entity>

n this case, the object musician has a relationship n p object with an instrument . This relationship is unidirectional.

The entity Musician contains a set I NSTRUMENT :

public class Musicien extends AuditableModel {
    ...
    @ManyToMany(fetch = FetchType.LAZY, cascade = { CascadeType.PERSIST, CascadeType.MERGE })
    private Set<Instrument> instruments;

    public Set<Instrument> getInstruments() {
        return instruments;
    }
    public void setInstruments(Set<Instrument> instruments) {
        this.instruments = instruments;
    }
    ...
}

To create a bidirectional relationship, the target entity also carries a many-to-many relationship to the entity master. This relationship must include a mappedBy attribute to the entity master.

<entity name="Musicien">
    ...
    <many-to-many name="instruments" ref="Instrument"/>
</entity>

<entity name="Instrument">
    ...
    <many-to-many name="musiciens" ref="Musicien" mappedBy="instruments"/>
</entity>