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Thread: Re: [GENERAL] MS Access 2007 update write conflict problem & resolution

Re: [GENERAL] MS Access 2007 update write conflict problem & resolution

From
"justin@magwerks.com"
Date:
The bigger problem is using time stamps to find the record for updating

Timestamps will not be unique as more than 1 record can have the same value

I suggest changing the updating method to use a unique key. 

---- Message from "Little, Douglas" <DOUGLAS.LITTLE@orbitz.com> at 03-19-2010 10:35:09 AM ------

Hi,

We’ve been struggling with an MS Access 2007 app that updates a PG table.   It was working,  and then it wasn’t. 

It looks like we recreated the table without specifying the precision on the timestamp columns.

 

PG is defaulting to timestamp(6), which doesn’t work with MS Access.  The finest precision Access can deal with is timestamp(3).

When the record is retrieved from PG it displays 6 microseconds,  when Access prepares the update, the value is rounded to 3 microseconds.

The update can’t then locate the row  (timestamp mismatch), and displays  the ‘write conflict’ error.

 

Altering the column to timestamp(0) corrected the issue.

 

2 questions

1-       PGAdmin was reporting the precision as 0, while a select was displaying 6 microseconds.  Is this a known bug in pgadmin?

2-      Is there a way in PG that I can set the default precision on timestamp?

Thanks

 

I’ll cross post to the pgadmin list for the pgadmin question.

 

Doug Little

 

Sr. Data Warehouse Architect | Enterprise Data Management | Orbitz Worldwide

500 W. Madison, Suite 1000  Chicago IL 60661| Office 312.260.2588 | Fax 312.894.5164 | Cell 847-997-5741

Douglas.Little@orbitz.com

 cid:image001.jpg@01CABEC8.D4980670  orbitz.com | ebookers.com | hotelclub.com | cheaptickets.com | ratestogo.com | asiahotels.com

 




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Thank you.

Re: [GENERAL] MS Access 2007 update write conflict problem & resolution

From
Richard Broersma
Date:
On Fri, Mar 19, 2010 at 11:12 AM, justin@magwerks.com
<justin@magwerks.com> wrote:
>
> The bigger problem is using time stamps to find the record for updating
>
> Timestamps will not be unique as more than 1 record can have the same value
>
> I suggest changing the updating method to use a unique key.

MS-Access achieves optimistic locking by listing all of the columns in
a table in the WHERE clause of the UPDATE statement.  If ms-access
unable to fully represent the data stored in a postgresql table,
Access will throw back update conflict errors when postgres doesn't
update the record due to the truncated data values.  I've also seen
this with null valued boolean fields.

Part of the solution would be configure the ODBC driver to use
PostgreSQL's xmin for optimistic locking.  Of-course this doesn't fix
MS-Accesses inability to handle the ranges of many of PG data-types.

--
Regards,
Richard Broersma Jr.

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