我正在使用Toplink Essentials（JPA）+ GlassFish v3 + NetBean 6.9

我有一个带有复合主键的表：

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

我创建了2个实体类，一个是实体本身，第二个是PK类。

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;

}

现在.. 我该如何在WHERE中用JPQL编写SELECT子句？

这失败了。

SELECT m FROM Machine m WHERE m.machineId = 10

http://www.mail-
archive.com/users@openjpa.apache.org/msg03073.html

根据网页，添加“ val”？不，它也失败。

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

在这两种情况下，错误均为：

    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].