PersistenceException "unknown state or association field" [message #756107] |
Thu, 10 November 2011 23:16 |
Shelli Orton Messages: 101 Registered: September 2009 |
Senior Member |
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I am trying to understand how to do (simple) joins in JPQL. I have two tables/entities: Parent and Child.
@Entity
@Table(name = "Parent")
@NamedQueries({
@NamedQuery(name = "Parent.findByStatus", query = "SELECT p FROM Parent p WHERE p.status = :status")})
public class Parent
{
private String parentId;
private Set<Child> children;
private String status;
public Parent()
{
// empty constructor
}
@Id
@Column(name = "PARENT_ID")
public String getParentId()
{
return parentId;
}
public void setParentId(String parentId)
{
this.parentId= parentId;
}
// bi-directional many-to-one association to Child
@OneToMany(mappedBy = "parent")
public Set<Child> getChildren()
{
return children;
}
public void setChildre(Set<Child> children)
{
this.children= children;
}
@Column(name = "STATUS")
public String getStatus()
{
return status;
}
public void setStatus(String status)
{
this.status = status;
}
}
@Entity
@NamedQueries({
@NamedQuery(name = "Child.findByStatus", query = "SELECT c FROM Child c WHERE c.status = :status"),
@NamedQuery(name = "Child.findByParentId", query = "SELECT c FROM Child c JOIN c.parent p WHERE p.parentId = :parentId"),
@NamedQuery(name = "Child.findByParentIdAndStatus", query = "SELECT c FROM Child c JOIN c.parent p WHERE p.parentId = :parentId AND c.status = :status") })
public class Child
{
private childId id;
private String status;
private Parent parent;
public Child()
{
// empty constructor
}
@Id
@Column(name = "CHILD_ID")
public String getChildId()
{
return childId;
}
public void setChildId(String childId)
{
this.childId= childId;
}
// bi-directional many-to-one association to Parent
@ManyToOne
@JoinColumn(name = "PARENT_ID")
public Parent getParent ()
{
return parent;
}
public void setParent(Parent parent)
{
this.parent= parent;
}
@Column(name = "STATUS")
public String getStatus()
{
return status;
}
public void setStatus(String status)
{
this.status = status;
}
}
But this causes the following exception:
Caused by: javax.persistence.PersistenceException: Exception [EclipseLink-8030] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Error compiling the query [Child.findByParentId: SELECT c FROM Child c JOIN c.parent p WHERE p.parentId = :parentId], line 1, column 47: unknown state or association field [parentId] of class [my.model.Parent].
It's my understanding that JPQL traverses the object model on JOINs. So, in the query:
SELECT c FROM Child c JOIN c.parent p WHERE p.parentId = :parentId
p is the fetched Parent object associated with the Child objects. If this is correct, then why I am getting the error? The Parent object has a parentId field and so should be okay, yes?
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