CMR in ejb 3.0

Question

I am getting the following error :
Exception Description: Multiple writable mappings exist for the field [ENVINCIDE
NTS.INCIDENTS_ID]. Only one may be defined as writable, all others must be spec
ified read-only.
for the entity bean envincidents:
@Id
@Column(name="INCIDENTS_ID", primaryKey=true, nullable=false)
public Long getIncidentsId() {
return incidentsId;
public void setIncidentsId(Long incidentsId) {
this.incidentsId = incidentsId;
@Id
@ManyToOne(targetEntity="model.Incidents")
@JoinColumn(name="ENVINCIDENTS.INCIDENTS_ID", referencedColumnName="INCIDENTS.ID")
public Incidents getIncidents() {
return incidents;
public void setIncidents(Incidents incidents) {
this.incidents = incidents;
how do I make one of them read only.

Answer 1

If you are mapping the same field to two attributes then you will have this issue.
You basically need to make one of the mappings read-only and this write your model to handle this and keep the values consistent. I would modify your model as:
@Id
@Column(name="INCIDENTS_ID", primaryKey=true, nullable=false, updatable=false, insertable=false)
public Long getIncidentsId() {
return incidentsId;
public void setIncidentsId(Long incidentsId) {
this.incidentsId = incidentsId;
@Id
@ManyToOne(targetEntity="model.Incidents")
@JoinColumn(name="ENVINCIDENTS.INCIDENTS_ID", referencedColumnName="INCIDENTS.ID")
public Incidents getIncidents() {
return incidents;
public void setIncidents(Incidents incidents) {
this.incidents = incidents;
setIncidentsId(incidents.getId());
}Note that the Basic mapping is qualified with updatable=false and insertable=false. These settings are equiavlent to TopLink's read-only setting on a mapping.
I hope this helps,
Doug