当目标是组合键时，Hibernate不保存ManyToOne

Question

Hibernate does not seem to be updating an FK reference when the object of that association is a composite key.

The transaction succeeds (no error, no stack trace), but there is no update statement generated (I have hibernate logging enabled).

I have tried all manner of cascade annotations (no cascade, ALL, PERSIST, even SAVE_UPDATE) without any change to the symptoms. This no-update symptom exists both from an on-line OpenXava screen as well as from custom Java code (in an OpenXava action).

The application database has requirements to allow external uploads to tables, so I have been told that switching to system-assigned keys is not an option they are willing to pursue.

The owning association (currently without any cascade setting):

  @ManyToOne(fetch=FetchType.LAZY,optional=false)
  @Required
  @JoinColumns({
    @JoinColumn(name="programID",referencedColumnName="programID",nullable=false,unique=false,insertable=false,updatable=false),
    @JoinColumn(name="projectID",referencedColumnName="projectID",nullable=false,unique=false,insertable=false,updatable=false)
  })
  @DescriptionsList(descriptionProperties="parentProgram.programName,projectName")
  @ReferenceView("reference")
  private Project associatedProject;

The inverse association:

  @OneToMany(mappedBy="associatedProject",fetch=FetchType.LAZY) //No cascade allowed
  @ReadOnly
  private Set<Asset> assets = new HashSet<Asset>();

Does anyone know if there is an open Hibernate bug on this? I have not been able to find any using Google search, but perhaps someone has first-hand experience.

Thanks, Roy.

EDIT: As a work-around, I tried to write my own HQL update.

update Asset set associatedProject = :ap where assetKey = :key

That fails on an obtuse Hibernate syntax error unexpected AST node: AND while processing the SET clause.

update Asset set associatedProject.projectId = :projId, associatedProject.parentProgram = :pgm where assetKey = :key

That generated update Asset cross join set projectID=?, programID=? where assetKey=? update Asset cross join set projectID=?, programID=? where assetKey=? and then failed on invalid syntax at "cross"

However, doing my own SQL update works.

Does anyone have a better work-around? Or any further thoughts on the root problem?

In my opinion, this still points to a Hibernate bug (of course it's a bug -- you can't just skip an update without any errors or messages) with composite key handling.

Answer 1

Hibernate does not save the relationship because you say it that doesn't save it. Just remove the insertable=false,updatable=false from your two @JoinColumn.

Answer 2

Here is a start on how you might use "derived identity" to map your primary keys, and this might help. I'm just guessing at your model. But it's a start....

@Entity
public class Program {
    @Id
    int id;

    @OneToMany(mappedBy="program")
    Set<Project> projects;

    ...
}

@Embeddable
public class ProjectID {
    int projectID;
    int programID; // corresponds to the type of Program's primary key

    ...
}

@Entity
public class Project {
    @EmbeddedId
    ProjectID id;

    @MapsId("programID") // maps 'programID' attribute of embedded ID
    @ManyToOne
    Program program;

    @OneToMany(mappedBy="associatedProject", fetch=FetchType.LAZY)
    Set<Asset> assets;

    ...
}

@Embeddable
public class AssetID {
    int assetID;
    ProjectID projectID; // corresponds to the type of Project's primary key

    ...
}

@Entity
public class Asset {
    @EmbeddedId
    AssetID id;

    @MapsId("projectID") // maps 'projectID' attribute of embedded ID
    @ManyToOne(fetch=FetchType.LAZY, optional=false)
    Project associatedProject;

    ...
}

Derived identities are discussed in the JPA 2.1 spec, section 2.4.1.