JPA Self join error - jpa-2.0

Question

I have an error with my entities, my tables are:
LANGUAGE
codLanguage (Primary Key)
nameLanguage
Device
idDevice(Primary Key) nameDevice
PHRASE
idPhraseGroup(Primary Key) codlanguage(Primary Key) idDevice
(Primary Key) tex
I have problem with my entity Phrase,it is :
public class Phrase implements Serializable {
#EmbeddedId
private PhraseKey idPhrase;
private String text;
//etc
//here my problem (*)
#OneToMany(mappedBy="idPhrase.idPhraseGroup",fetch=FetchType.EAGER)
#JoinColumn(name = "idPhrase.idPhraseGroup", updatable = false, insertable = false, referencedColumnName = "idPhrase.idPhraseGroup")
private List<Phrase> groupListPhrase;
}
#Embeddable
public class PhraseKey implements Serializable {
private Integer idPhraseGroup;
private String codLanguage;
private String idDevice;
---getter e setter
}
I would you like to get a list of phrases with the same idPhraseGroup
for example in Phrase table :
idPhraseGroup | codLang |idDevice | text
1 | ES | 1 | mesa
1 | EN | 1 | table
..but i've got this error:
Exception Description: An incompatible mapping has been encountered
This usually occurs when the cardinality of a mapping does not
correspond with the cardinality of its backpointer
Thanxs

Answer 1

I do not see why you need the mapping, or how it can work. You cannot use the basic mapping "idPhrase.idPhraseGroup" field in the mappedBy on a oneToMany because it does not describe a relationship. A oneToMany generally relies on the other side having a manyToOne back, but in this case you dont.
If all you want is a collection of Phrase entities with a particular idPhaseGroup, just query for it using:
em.createQuery("select p from Phase p where p.idPhrase.idPhraseGroup = :phaseGroup").setParameter("phaseGroup", phaseGroupId);
I would remove the mapping unless you really need it cached within the Phaze entity. If you do, it would be better mapped like:
#OneToMany
#JoinColumn(name="IDPHASEGROUP", referencedColumnName="IDPHASEGROUP", insertable=false, updatable=false)
private List groupListPhrase;