unnecessary update action when save object

smallufo · **Posted:** Tue Feb 27, 2007 12:55 pm

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Hibernate version: hibernate-3.2

This is my scenario :

Item and Category are many-to-many relation , the owning side is Item.
Item and Image are one-to-many relation , Image(DELETE_ORPHAN) is dependent on Item :

Code:

In Item.java :
  @OneToMany( fetch=FetchType.EAGER )
  @Cascade(value = {CascadeType.SAVE_UPDATE , CascadeType.DELETE_ORPHAN} )
  @JoinColumn(name="ItemID")
  @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
  private Set<Image>   images   = new HashSet<Image>();

When I create a new Item , add Images , add Categories , and save it (using getHibernateTemplate().save(newItem) ) ; the SQL dump is as following :

Code:

Hibernate: insert into Item (uuid, ....) values (?, ....)
Hibernate: insert into Image (data, size, ....) values (?, ?,...)
Hibernate: insert into Image (data, size, ....) values (?, ?,...)
Hibernate: insert into Image (data, size, ....) values (?, ?,...)
Hibernate: insert into Image (data, size, ....) values (?, ?,...)
Hibernate: insert into Item_Category (ItemID, CategoryID) values (?, ?)
Hibernate: update Image set ItemID=? where ID=?
Hibernate: update Image set ItemID=? where ID=?
Hibernate: update Image set ItemID=? where ID=?
Hibernate: update Image set ItemID=? where ID=?

I noticed that hibernate does redundant 'update' actions.
It seems that adding category to item makes hibernate think the item is updated , but it does not related to item's Image set...
How to avoid the redundant update actions ?

I tried to change the CascadeType to :
@Cascade(value = {CascadeType.PERSIST , CascadeType.DELETE_ORPHAN} )
But it throws TransientObjectException :

Code:

Caused by: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: foo.bar.Image

Maybe getHibernateTemplate().persist(newItem) can solve the problem , but persist doesn't return the generated identifier.

What should I do ?

dharmendra.pandey · **Posted:** Wed Feb 28, 2007 12:20 am

Hi smallufo,

try Bidirectional mapping with inverse =true in set .That will reduce your extra update

smallufo · **Posted:** Wed Feb 28, 2007 1:36 am

Quote:

try Bidirectional mapping with inverse =true in set .That will reduce your extra update

Hi , but I don't want Item and Image are bi-directional.
Any other suggestions ?

dharmendra.pandey · **Posted:** Wed Feb 28, 2007 2:17 am

Hi smallufo,

you will have to choose one of the either bi-directional or extra update. One quick hack is that use inverse="true" you should have foreign key and in child use insert false update false for that column. Might work .

smallufo · **Posted:** Wed Feb 28, 2007 4:24 pm

dharmendra.pandey wrote:

Hi smallufo,

you will have to choose one of the either bi-directional or extra update. One quick hack is that use inverse="true" you should have foreign key and in child use insert false update false for that column. Might work .

Thank you , but after I modify the relationship to bi-directional , there are still redundant update actions :

Code:

In Item.java :
  @OneToMany(fetch=FetchType.EAGER)
  @JoinColumn(name="ItemID")
  @Cascade(value = {CascadeType.SAVE_UPDATE , CascadeType.DELETE_ORPHAN} )
  @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
  private Set<Image>   images   = new HashSet<Image>();

Code:

In Image.java :
  @ManyToOne()
  @JoinColumn(name="ItemID" , insertable=false, updatable=false)
  protected Item item;

Why ? anything missed ?
Does it related to the missing inverse="true" ? I don't know where to add ...
I tried to add to here :

Code:

In Item.java : 
@OneToMany(fetch=FetchType.EAGER , mappedBy="item")

But I got an AnnotationException: mappedBy reference an unknown target entity property: foobar.Image.item in foobar.Item.images

smallufo · **Posted:** Wed Feb 28, 2007 5:07 pm

I found the problem .

In fact , the Image class is abstract , I have to copy this

Code:

  @ManyToOne()
  @JoinColumn(name="ItemID" , insertable=false, updatable=false)
  protected Item item;

to classes that inherit it.

And this solves the duplicated UPDATE actions problem.

This raises another question : why should I copy the item field to its (Image's) descendants ... ? It should be inheritanced...

dharmendra.pandey · **Posted:** Wed Feb 28, 2007 11:59 pm

Hi smallufo,

Have a reference

http://simoes.org/docs/hibernate-2.1/155.html

I don't know how to do by annotation