Hibernate返回错误的结果集并生成错误的查询

Question

I have a table which can referance on itself.

organisation(id,child_from_Org, ...)

Hibernate Mapping

@Entity
@Table(name = "organisation")
public class Organisation implements java.io.Serializable {

  private Integer id;
  private Organisation organisation;
  private ...

  @Id
  @GeneratedValue(strategy = IDENTITY)
  @Column(name = "id", unique = true, nullable = false)
  public Integer getId() {
    return this.id;
  }

  public void setId(Integer id) {
    this.id = id;
  }

  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "child_from_Org")
  public Organisation getOrganisation() {
    return this.organisation;
  }

  public void setOrganisation(Organisation organisation) {
    this.organisation = organisation;
  }
  ...
}

If i execute aa hibernate query like "from Organisation", then i'll get all organisations.

from Organisation o where o.id = 1

Then i get the organisation with id 1

from Organisation o where o.id = 1 or o.organisation.id = 1

Returns organisation with id 1 and all child organisations

from Organisation o where o.id = 1 or o.organisation.id = 1 or o.organisation.organisation.id = 1

Does not return the organisation with id 1!!!! Why? I tried all possible combinations with braclets (() or () or ()).

I looks like a wrong SQL is getting generated from hibernate:

select  organisati0_.id as id470_,
  organisati0_.child_from_Org as ist21_470_,70_,
  ,...
 from
  organisation organisati0_ cross 
 join
  organisation organisati1_ 
 where
  organisati0_.child_from_Org=organisati1_.id 
  and (
   organisati0_.id=1 
   or organisati0_.child_from_Org=1 
   or organisati1_.child_from_Org=1
  )

How can i resolve that problem?

Answer 1

Because you have an implicit join from Organisation to itself, and in hibernate implicit joins are inner joins:

http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/queryhql.html#queryhql-joins-forms

The implicit form does not use the join keyword. Instead, the associations are "dereferenced" using dot-notation. implicit joins can appear in any of the HQL clauses. implicit join result in inner joins in the resulting SQL statement.

Try explicit left joins, eg:

select o from Organisation as o left join o.organisation as parent left join parent.organisation as grandparent where o.id = 1 or parent.id = 1 or grandparent.id = 1

( NOTE: I've assumed organization.organisation is a parent relationship. If that's not the case you can(and should) replace the parent and grandparent aliases with something more appropriate)

EDITED TO ADD:

It seems what's happening is that the inner join is ruling out org with id of 1, probably because org with id of 1 has a null organisation

EDITED AGAIN TO ADD: Added select per comment below.