Re: To-one relationship not updated

Mon, 13 Nov 2006 09:37:30 -0800

Calven,

Before going much further, please check the model for your MySQL database to make sure your are using DATETIME for all your date/time columns and not TIMESTAMP.

In MySQL the TIMESTAMP is a special auto-updating field and this confuses EOF's optimistic locking scheme.  While you are in there, also make sure you do not include column types for locking that may be approximate values (these would include float, double, etc.).

On Nov 13, 2006, at 10:00 AM, Calven Eggert wrote:

Yes, I commit the changes with myEditingContext.saveChanges().

Since this morning, I have changed the call to myEditingContext.invalidateAllObjects to Invalidating the Task record, using the method:

NSMutableArray ids = new NSMutableArray();
ids.addObject(myEditingContext.globalIDForObject(curTask));
myEditingContext.invalidateObjectsWithGlobalIDs(ids);

This again works, but  I discovered that invalidating the relationship does not solve the problem.  Also discovered that this is not a problem in my Oracle database but only using my MySQL database.  Can anyone shed any light on this?

Still, I am hoping that there is another way to solve this. I'd hate to have to invalidate everything every time I make a change.



On Monday, November 13, 2006, at 09:45AM, "Daniele Corti" <[EMAIL PROTECTED]> wrote:
well, do you commit the database after the first call of assignedTo? I
mean if you call yourEditingContext.saveChanges()

2006/11/13, Calven Eggert <[EMAIL PROTECTED]>:

 Hi all,

 I have a EOEnterpriseObject, called a Task record and it has a
relationship, called AssignedTo, that connects to another EOEnterprise
record called Identity.  In my WO Application, when I assign an Identity to
the Task record thus creating the AssignedTo relationship, it works the
first time, but if I do it again immediately after, it then gives me the
error:

 updateValuesInRowDescribedByQualifier --
com.webobjects.jdbcadaptor.JDBCChannel method failed to
update row in database
 com.webobjects.eoaccess.EOGeneralAdaptorException:
updateValuesInRowDescribedByQualifier --
com.webobjects.jdbcadaptor.JDBCChannel method failed to
update row in database
     at
com.webobjects.eoaccess.EODatabaseContext._exceptionWithDatabaseContextInformationAdded(EODatabaseContext.java:4685)
     at
com.webobjects.eoaccess.EODatabaseContext.performChanges(EODatabaseContext.java:6393)
     at
com.webobjects.eocontrol.EOObjectStoreCoordinator.saveChangesInEditingContext(EOObjectStoreCoordinator.java:415)


 Just recently getting a basic understanding on how WebObjects works and
deals with snapshots, thanks to Chuck Hill's book "Practical WebObjects", I
figured that the snapshot of the Task record, or actually the relationship
AssignedTo, must not be updated after the first assignment is set.  After
putting in the line EditingContext.invalidateAllObjects(),
the problem went away.  I know this isn't the best way to do this.  But I
thought that to-one relationships were suppose to be ok and the to-many
needed to be babysat.  I've also tried
setRefreshesRefetchedObjects(True) but this didn't work, I
assume because I'm not actually going to the db after my save for a refetch.
I've also tried setDefaultTimestampLag(2) but that didn't work either.

 Could someone please help me understand what is going on here?  Suggested
readings would also be greatly appreciated.

 Thanks,
 Calven

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-- 
Daniele Corti
AIM: S0CR4TE5


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