[Zope] Determining Success or Failure status on SQL update in ZSQL Metho d d

[Ira Hochman]

Thanks for the response.  It sounds right to me, but the sql method seems to
return an object.  My skill with Zope or Python is not quite at the level
where I know how to interrogate this object for a record count.

When I use the following test code (where upd is the id of the SQLMethod)

  <dtml-let foo="upd()">
  foo is <dtml-var foo>
  </dtml-let>

I get back

  foo is <Shared.DC.ZRDB.RDB.DatabaseResults instance at e7fef0>

Right now I am trying out a SELECT with a <dtml-raise> prior to issuing the
update.  It's non-atomic and thus not ideal, but is an acceptable workaround
until I can find a production worthy solution.

I am still open to any and all suggestions.

BTW, once I figure this out, I am definitely going to write it up.  Would
this be a tip or a howto?

--ira

-----Original Message-----
From: Matthew Parslow [mailto:matt@umd.com.au]
Sent: Wednesday, February 16, 2000 11:33 PM
To: Ira Hochman; zope@zope.org
Subject: Re: [Zope] Determining Success or Failure status on SQL update
in ZSQL Metho d d


what about <dtml-let "rows_affected=sql_query(params=param)">?
and then check if rows_affected is >0

Regards,
Matthew Parslow

On Thu, 17 Feb 2000, you wrote:
> Hello,
> 
> A search of prior discussion threads shows this question occasionally
> appears without resolution.  Perhaps someone has found an answer to it
since
> then, so here it is...
> 
> Using a ZSQL method, how do I detect if any rows have been affected when
> performing a SQL UPDATE.  I do not need to know how many rows, just
whether
> the statement affected 0 rows or more than 0 rows.
> 
> My environment is Oracle (7 & 8) and with other programmatic interfaces to
> Oracle, one can capture a (non-error) return status that indicates if no
> rows were affected.  This is supported in the ODBC API for Oracle and
other
> databases as well.  Is there a way to capture this return status even
though
> it is not flagged as an error?  
> 
> No dtml-try since it's only a return code, not an error code
> 
> As a workaround I've tried to do a select count, but to do this I need to
>  1) execute the select and update in the same transaction and
>  2) run the select before the update, store the value, then return it at
the
> end (the update may or will change at least one of the fields referenced
in
> the where clause, so I cannot run it after)
> 
> So, inside of a SQL method, I can do #1, but cannot see a way to do #2.
> 
> Is there a secret trick to this or is it a case of adding code to the
> existing DAs?  Please please tell me it's the former.
> 
> Thanks in advance,
> Ira
> 
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