Hi Ravi,
Yes, calling getters on Subject within a transaction results in update statements. The update
is on MC_SUBJECT.
I'm using Spring Transaction for the transaction management.
I will try to consolidate some of my code so you can have a full picture how openjpa is used
in this project.
Thanks,
Cheng
> -----Original Message-----
> From: Ravi Palacherla [mailto:ravi.palacherla@oracle.com]
> Sent: Thursday, March 04, 2010 10:02 AM 无住生什么心？
> To: users@openjpa.apache.org
> Subject: RE: unexpected update when using many to many relationship
>
> Hi Cheng,
>
> >> I just read some Subject records
> Do you mean calling getters on Subject with in a transaction, results in
> update statement ?
> I do not think it is an expected behavior.
>
> Is the update statement on "MC_SUBJECT" table ?
> I understand from the code snippet you pasted; that it a self-referential
> many2many relationship between subject and subject, correct ?
> I think pasting the code snippet that reads subject records ( actually all
> the code that is called inside the transaction) will help.
>
> Also what type of persistence context are you using, extended or
> transaction ?
>
> Regards,
> Ravi.
>
> -----Original Message-----
> From: Cheng Zhang [mailto:chzhang@yahoo-inc.com]
> Sent: Thursday, March 04, 2010 10:38 AM
> To: users@openjpa.apache.org
> Subject: unexpected update when using many to many relationship
>
> Hi,
>
>
>
> I found that, if I use many-to-many relationship, there will be
> unexpected update when the transaction is closed.
>
>
>
> Here is my code,
>
>
>
> @Entity
>
> @Table(name = "MC_SUBJECT")
>
> public class Subject implements Serializable {
>
> @Id
>
> @Column(length=64)
>
> private String id;
>
>
>
> @Column
>
> private Date createdDate;
>
>
>
> @Column
>
> private String createdBy;
>
>
>
> @Column(length=128, nullable=false)
>
> private String title;
>
>
>
> @Column(length=128, nullable=false)
>
> private String subjectType;
>
>
>
> @Column(length=2048)
>
> private String description;
>
>
>
> @Column
>
> private Date modifiedDate;
>
>
>
> @Column
>
> private String modifiedBy;
>
>
>
> @ManyToMany(fetch=FetchType.LAZY)
>
> @JoinTable(name = "MC_CHILD_SUBJECT", joinColumns = {
> @JoinColumn(name = "SUBJECT_KEY") }, inverseJoinColumns = {
> @JoinColumn(name = "CHILD_SUBJECT_KEY") })
>
> private List<Subject> childSubjectCollection;
>
>
>
> ...... getters and setters
>
> }
>
>
>
> In my code, I just read some Subject records. In the log file, I can see
> some update statement.
>
>
>
> However, if I change the many-to-many to one-to-many, everything is fine
> and no update.
>
>
>
> Is it expected behavior?
>
>
>
> Thanks,
>
>
>
> Cheng
>
>
>
>
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