Hello,

I use SEAM - generated (and customized later on) entities. They contain  @EmbeddedId which is suitable because my tables doesn't have unique id as a single column so composite is in use by means of @EmbeddedId / @Embeddable.

The problem is that Query returns null object.

My question - what is the problem that such a query returns null and which solution is applicable??

Thank you in advance

{code}

query = "SELECT t FROM Gm3 t where t.id.apb=:apb";
final Gm3 gm3;
try {
gm3 = (Gm3) entityManager.createQuery(query).setParameter("apb", this.apb).getSingleResult();
} catch (NoResultException e) {
throw new RuntimeException("Can't read from GM3. " + query, e);
} catch (Exception e) {
throw new RuntimeException("Can't read from GM3. " + query, e);
} {code}

Entity:

{code}

@Entity
@Table(name = "GM3")
public class Gm3 implements java.io.Serializable {

private Gm3Id id;

public Gm3() {
}

public Gm3(Gm3Id id) {
this.id = id;
}

@EmbeddedId
@AttributeOverrides({@AttributeOverride(name = "apb",  nullable = true,column = @Column(name = "APB", length = 8)),
@AttributeOverride(name = "nummer", column = @Column(name = "NUMMER", length = 2)),
@AttributeOverride(name = "id", column = @Column(name = "ID", length = 10))})
public Gm3Id getId() {
return this.id;
}

public void setId(Gm3Id id) {
this.id = id;
}

private String taal;
private String stars;
private String national;
private Date ndatum;
private Date nstop;
private String dosis;
private String n1;
private String multiply;
private String prijs;
private String bprijs;
private Date pdatum;
private Date bpdatum;
private String rg1;
private String rg2;

. . .
{code}

{code}

@Embeddable
public class Gm3Id implements java.io.Serializable {

private String apb;
private String nummer;
private String id;

public Gm3Id() {
}

public Gm3Id(String apb, String nummer, String id) {
this.apb = apb;
this.nummer = nummer;
this.id = id;
}

@Column(name = "APB", length = 8)
public String getApb() {
return this.apb;
}

public void setApb(String apb) {
this.apb = apb;
}

@Column(name = "NUMMER", length = 2)
public String getNummer() {
return this.nummer;
}

public void setNummer(String nummer) {
this.nummer = nummer;
}

@Column(name = "ID", length = 10)
public String getId() {
return this.id;
}

public void setId(String id) {
this.id = id;
}

public boolean equals(Object other) {
if ((this == other))
return true;
if ((other == null))
return false;
if (!(other instanceof Gm3Id))
return false;
Gm3Id castOther = (Gm3Id) other;

return ((this.getApb() == castOther.getApb()) || (this.getApb() != null && castOther.getApb() != null && this
.getApb().equals(castOther.getApb())))
&& ((this.getNummer() == castOther.getNummer()) || (this.getNummer() != null
&& castOther.getNummer() != null && this.getNummer().equals(castOther.getNummer())))
&& ((this.getId() == castOther.getId()) || (this.getId() != null && castOther.getId() != null && this
.getId().equals(castOther.getId())));
}

public int hashCode() {
int result = 17;
result = 37 * result + (getApb() == null ? 0 : this.getApb().hashCode());
result = 37 * result + (getNummer() == null ? 0 : this.getNummer().hashCode());
return result;
}

}

{code}