Hi Patrick and Reece,
Thanks for your answers. I should have been more clear in my questions.
Patrick Linskey wrote:
1) Does OpenJPA create before images for rollback? Or is the transaction
rollback functionality just implemented in the JDO closed source? As
Reece mentions, we'd need before image values on relationships for
dependency calculation in case of unique keys.
OpenJPA can do that, yes. You need to configure things accordingly,
but the feature is definitely there. See the RetainValues property.
2) Why are updates ignored (not re-ordered) in ConstraintUpdateManager,
if there are *no* delete-then-insert-same-pk?
The graph is walked, which will potentially re-order the updates. What
bit of code are you referring to?
In ConstraintUpdateManager#analyzeForeignKeys line 157, there is this
boolean flag ignoreUpdates. Maybe it's just the name that confuses me,
but why are updates re-ordered if there are delete-then-insert-same-pk,
and otherwise not? I.e. what requires updates to be considered in the
delete-then-insert-same-pk case? Also, if ignoreUpdate is true in line
188, the updates would be executed in random order, correct?
3) Can foreign keys be used in the WHERE clause for updates/deletes?
Yes -- what type of query are you looking for in particular?
I was wondering about lines like
sm = row.getForeignKeySet(fks[i]);
if (sm == null)
sm = row.getForeignKeyWhere(fks[i]);
Do "-Set" and "-Where" mean the SET and WHERE clause of a SQL (UPDATE)
statement? What are the values in ForeignKeyWhere? Aren't these before
image values? Also, I expect updates to be done referencing pk columns
only, like WHERE pk1 = ?, ..., pkN = ?
Thanks again,
-- markus.
-Patrick
On 6/7/07, Markus Fuchs <[EMAIL PROTECTED]> wrote:
Hi all,
could somebody please answer these questions?
1) Does OpenJPA create before images for rollback? Or is the transaction
rollback functionality just implemented in the JDO closed source? As
Reece mentions, we'd need before image values on relationships for
dependency calculation in case of unique keys.
2) Why are updates ignored (not re-ordered) in ConstraintUpdateManager,
if there are *no* delete-then-insert-same-pk?
3) Can foreign keys be used in the WHERE clause for updates/deletes?
Thanks so much!
-- markus.
