相关疑难解决方法(0)

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

我有一个复合主键表:

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

我为实体本身创建了两个实体类,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.. 如何使用JPERE用WHERE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,它也失败了.

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

在这两种情况下,错误是:

    Exception Description: Error compiling the …