ejb@glassfish.java.net

retrieving data from two related entities(table)

From: Eve Pokua <gorgeous65_at_msn.com>
Date: Wed, 25 Apr 2007 15:55:58 +0100

Hello everyone,

I have two ralated entities as below:

Usersent

and

Machineent

the relation is one user to many machines. So each machine must have at
least one user.

So the relation is specify as:
public class Machineent......{
@Id
    @Column(name = "COMPUTNAME", nullable = false)
    private String comptername;
......
@ManyToOne()
    @JoinColumn(name="USERID")
    private Usersent usersent;

and:

public class Usersent.........
@Id
    @Column(name="USERID", nullable=false)
    private String UserID;
..........

@OneToMany(mappedBy="usersent")
    private List <Machineent> machineents;

Now in the Machineent I have specified methods which should be used to set
and get data from the database of the Usersent table


public Usersent getUserID() {
        return usersent;
    }

    public void setUserID(String UserID) {
        this.usersent = usersent;}


I have a query as:

@NamedQuery(name = "Machineent.findMachinebyuser",query = "SELECT us FROM
Usersent us WHERE us.UserID=:UserID")

I also tried the following query.

@NamedQuery(name = "Machineent.findMachinebyuser",query = "SELECT m FROM
Machineent m JOIN m.usersent us WHERE us.UserID=:UserID"),

In my client I have:

List<Machineent> machineent =machbean.searchbyusername("u");



for (Machineent allmachlist: machineent){


out.println("<td>");
out.println(allmachlist.getcompModle());out.println("</td>");
        out.println("<td>");
out.println(allmachlist.getcomptername());out.println("</td>");
        out.println("<td>");
out.println(allmachlist.getUserID());out.println("</td>");
      }

but it does not do exactly what I am looking for. The bottom line is, I
would like to able to retrieve data from both or either tables of the
entities. What is the best way to go about this?

Thanks

eve

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