The way the spec was changed near the end of the cycle, both sides of a relationship need to be consistent, both in the datastore and in memory after a flush operation.
This would be a candidate for a new TCK test to be released with a maintenance update of JDO.
The result you obtained should only be possible if both sides of the relationship were mapped to different columns in the datastore.
Craig <spec>If two relationships (one on each side of an association) are mapped to the same column, the field on only one side of the association needs to be explicitly mapped. The field on the other side of the relationship can be mapped by using the mapped-by at- tribute identifying the field on the side that defines the mapping. Regardless of which side changes the relationship, flush (whether done as part of commit or explicitly by the user) will modify the datastore to reflect the change and will update the memory model for con- sistency. There is no further behavior implied by having both sides of the relationship map to the same database column(s). In particular, making a change to one side of the relation- ship does not imply any runtime behavior by the JDO implementation to change the other side of the relationship in memory prior to flush, and there is no requirement to load fields affected by the change if they are not already loaded. This implies that if the RetainVal- ues flag or DetachAllOnCommit is set to true, and the relationship field is loaded, then the implementation will change the field on the other side so it is visible after transaction
completion.Conflicting changes to relationships cause a JDOUserException to be thrown at flush
time. Conflicting changes include:•adding a related instance with a single-valued mapped-by relationship field to
more than one one-to-many collection relationship•setting both sides of a one-to-one relationship such that they do not refer to each
other </spec> On May 17, 2006, at 12:07 PM, Michael Bouschen wrote:
Hi Jörg,you can create an unique index on the FK in the database. This still does not automatically update the other side of the relationship. But it prevents storing unexpected relationship values into the database, because the transaction would fail if a2 still refers b2.The JDO implementation might support managing bidirectional relationships in memory, but this is not mandated by the spec.Regards MichaelEric Samson schrieb:I see. Hm. Well. For this relationship, being "bidirectional" seems to be equivalent to "being 1:1". Confusing./In particular, I'd expect a2 not pointing to b2 anymore, as this clearly is supposed to be is a 1:1 relationship. The implementation can determine this being a 1:1 association, as there are two corresponding fields, and consequently it should issue /Bu default, there is no 1:1 relationships either in Java or in RDBMS.If you want to insure this 1:1 bi-directional link you have to: * use some triggers in your db * use a JDO callback * do it cleanly in your set /getters in Java * use an ORM tool that can manage 1:1 bi-directional linksAnyway, thanks for your answer! Regards, Jörg-- Michael Bouschen [EMAIL PROTECTED] Engineering GmbH mailto:[EMAIL PROTECTED] http://www.tech.spree.de/ Tel.:++49/30/235 520-33 Buelowstr. 66 Fax.:++49/30/2175 2012 D-10783 Berlin
Craig Russell Architect, Sun Java Enterprise System http://java.sun.com/products/jdo 408 276-5638 mailto:[EMAIL PROTECTED] P.S. A good JDO? O, Gasp!
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