On Apr 2, 2008, at 4:30 AM, David Avendasora wrote:
The fact that Chuck didn't come up with this makes me doubt my
memory, but...
It seems that when I've run into this in my applications, it usually
means that between the time the EO was read out of the database, and
the time it is written back in, something in one of the locking
fields changed, or the field isn't "locking-friendly" in that WO has
a difficult time reading the datatype of the DB field and converting
it into the requested Java datatype and then converting it back and
coming up with the original value. I know with MS SQL Server that
long text fields are a problem.
I _believe_ (please correct me if I'm wrong) when EOF does an
update, it does it along the lines of "UPDATE TABLE WHERE
ATTRIBUTE_1 = x, ATTRIBUTE2 = y, etc" where the attribute values are
from the original reading of the record.
The problem is that the UPDATE can't find any records matching the
original attributes, and therefore didn't "select" any rows for
updating.
Dave
On Apr 1, 2008, at 6:06 PM, Johan Henselmans wrote:
Error:
com.webobjects.eoaccess.EOGeneralAdaptorException:
lockRowComparingAttributes --
com.webobjects.jdbcadaptor.JDBCChannel: lock operation failed to
select any rows
Close, but no rabbit stamp. What you are talking about produces an
optimistic locking expection and "update operation failed to update
any rows" from the channel. What Johan is hitting is an SQL statement
like SELECT ... FOR LOCK. That is pessimistic locking.
That said, I think that we did look at a case where you had this
problem. I just can't recall what the cause was.
Chuck
--
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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