Hi

I have a JSF form with multiple input fields, they values are passed to
a facade session bean, wich in turn accesses an ejb3 entity bean. The
DB contains a structure like this:


and the entity bean is mapped on 'Table A'. Is there a way to define a NamedQuery like this?

Sure.
Why not?
Have you had any problems?

Hi alesj

Yes, I have problems. It seams that the join conditions (a.id = ab.id.id_a, ab.id.id_b = b.id) are the problem.
Have you any suggestion?

A JAVA classes are these:

--------- A -------------
import java.util.*;
import javax.persistence.*;

@Entity
@Table(name = "A")
@NamedQueries({
@NamedQuery(name="getAByParameters",
query="SELECT OBJECT(a)
FROM A AS a,
AB AS ab,
B AS b
WHERE a.id = ab.id.id_a
AND ab.id.id_b = b.id
AND b.name like :p_name")
})
public class A implements java.io.Serializable {

private static final Logger log = Logger.getLogger(A.class);
private int id;
private Date date;
private Collection<B> bs = new ArrayList<B>(0);

public A() {
}

public A(int id,
Date date) {
this.id = id;
}

public A(int id,
Date date,
Collection<b> p_bs) {
this.id = id;
this.date = date;
this.bs = p_bs;
}

@Id
@Column(name="ID")
public int getId() { return this.id; }
public void setId(int id) { this.id = id; }

@Column(name="DATE")
public Date getDate() { return this.date; }
public void setDate(Date date) { this.date = date; }

@ManyToMany
@JoinTable(name="AB",
joinColumns={@JoinColumn(name="id_a")},
inverseJoinColumns={@JoinColumn(name="id_b")}
)
public Collection<B> getBs() { return this.bs; }
public void setBs(Collection<B> p_bs) { this.bs = p_bs; }

}

-------------- AB -----------------
import java.util.*;
import javax.persistence.*;

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

private ABId id;

public AB() {
}

public AB(ABId id) {
this.id = id;
}

@EmbeddedId
public ABId getId() { return this.id; }
public void setId(ABId id) { this.id = id; }

}

------------------- ABId ------------
import javax.persistence.*;

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

private int id_a;
private int id_b;

public ABId() {
}

public ABId(int id_a, int id_b) {
this.id_a = id_a;
this.id_b = id_b;
}

@Column(name="ID_A")
public int getId_a() { return this.id_a; }
public void setId_a(int id_a) { this.id_a = id_a; }

@Column(name="ID_B")
public int getId_b() { return this.id_b; }
public void setId_b(int id_b) { this.id_b = id_b; }

public boolean equals(Object other) {
if ( (this == other ) ) return true;
if ( (other == null ) ) return false;
if ( !(other instanceof ABId) ) return false;
ABId castOther = ( ABId ) other;
return (this.getId_a()==castOther.getId_a())
&& (this.getId_b()==castOther.getId_b());
}

public int hashCode() {
int result = 17;
result = 37 * result + this.getId_a();
result = 37 * result + this.getId_b();
return result;
}
}


--------------------- B -----------------------
import java.util.*;
import javax.persistence.*;

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

private int id;
private String name;
private Collection<A> as = new ArrayList<A>(0);

public B() {
}

public B(int id,
String name) {
this.id = id;
this.name = name;
}

public B(int id,
String name,
Collection<A> as) {
this.id = id;
this.name = name;
this.as = as;
}

@Id
@Column(name="ID")
public int getId() { return this.id; }
public void setId(int id) { this.id = id; }

@Column(name="name")
public String getName() { return this.name; }
public void setName(String name) { this.name = name; }

@ManyToMany
@JoinTable(name="AB",
joinColumns={@JoinColumn(name="id_b")},
inverseJoinColumns={@JoinColumn(name="id_a")}
)
public Collection<A> getAs() { return this.as; }
public void setAs(Collection<A> as) { this.as = as; }
}

Use simple composite many-to-one id on AB class.



Find the equivalent annotations to this xml, if you want to use just annotations.

Than in query use plain object oriented HQL.
It should work.