How to write JPQL SELECT with embedded id?

Question

I'm using Toplink essentials (JPA) + GlassFish v3 + NetBean 6.9

I have one table with composite primary key:

table (machine) ---------------- |PK machineId  | |PK workId     | |              | |______________| 

I created 2 entity classes one for entity itself and second is PK class.

public class Machine {    @EmbeddedId    protected MachinePK machinePK;     //getter setters of fields.. }  public class MachinePK {     @Column(name = "machineId")     private String machineId;      @Column(name = "workId")     private String workId;  } 

Now.. how do I write SELECT clause with JPQL with WHERE???

This fails.

SELECT m FROM Machine m WHERE m.machineId = 10 

http://www.mail-archive.com/[email protected]/msg03073.html

According to the web page, add "val"? No it fails too.

   SELECT m FROM Machine m WHERE m.machineId.val = 10 

In both case, the error is:

    Exception Description: Error compiling the query  [SELECT m FROM Machine m WHERE m.machineId.val = 10],  line 1, column 30: unknown state or association field  [MachineId] of class [entity.Machine]. 

Answer 1

SELECT m FROM Machine m WHERE m.machinePK.machineId = 10 

Answer 2

Tested with Hibernate 4.1 and JPA 2.0

Make the following changes in order to work:

Class Machine.java

public class Machine {    @EmbeddedId    protected MachinePK machinePK;     //getter & setters... } 

Class MachinePK.java

@Embeddable public class MachinePK {     @Column(name = "machineId")     private String machineId;      @Column(name = "workId")     private String workId;      //getter & setters... } 

...and for the JPQL query pass all column names:

Query query = em.createQuery("SELECT c.machinePK.machineId, c.machinePK.workId, "                 + "FROM Machine c WHERE c.machinePK.machineId=?"); query.setParameter(1, "10");  Collection results = query.getResultList();  Object[] obj = null; List<MachinePK> objPKList = new ArrayList<MachinePK>(); MachinePK objPK = null; Iterator it = results.iterator(); while(it.hasNext()){     obj = (Object[]) it.next();     objPK = new MachinePK();     objPK.setMachineId((String)obj[0]);     objPK.setWorkId((String)obj[1]);     objPKList.add(objPK);     System.out.println(objPK.getMachineId()); }