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Re: Documentation, assignment in expression.

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On 03/25/12 17:59, Dennis Lee Bieber wrote:
> On Sun, 25 Mar 2012 08:48:31 -0500, Tim Chase
>> Yeah, it has the same structure internally, but I'm somewhat
>> surprised that the DB connection object doesn't have an
>> __iter__() that does something like this automatically under the
>> covers.
>>
> 	I believe being able to use the connection object directly for
> queries is considered a short-cut feature... If you use the longer form
>
> con = db.connect()
> cur = con.cursor()
>
> 	the cursor object, in all that I've worked with, does function for
> iteration
>
> 	for rec in cur:
> 		#do stuff

Interesting.  Either this is something special for a particular 
DB back-end, or has been added since I went hunting (back with 
mxODBC and Python2.4).  I wouldn't be surprised if the latter was 
the case, as my code is nigh identical to yours.

  conn = db.DriverConnect(connection_string)
  cursor = conn.cursor()
  cursor.execute(sql, params)
  for row in cursor: # in the above 2.4 + mxODBC, this fails
    process(row)

I'd be interested to know the underlying implementation's 
efficiency, hopefully using .fetchmany() under the hood.  My 
understanding is that the .fetchmany() loop is the best way to do 
it, as the .fetchone() gets chatty with the DB (but is more 
efficient if you only need one row from a multi-result query), 
and the .fetchall() can blow out memory on large datasets.

-tkc

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Documentation, assignment in expression. Alexander Blinne <news@blinne.net> - 2012-03-23 23:59 +0100
  Re: Documentation, assignment in expression. Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-03-23 21:09 -0400
    Re: Documentation, assignment in expression. Alexander Blinne <news@blinne.net> - 2012-03-25 14:18 +0200
      Re: Documentation, assignment in expression. Tim Chase <python.list@tim.thechases.com> - 2012-03-25 08:03 -0500
        Re: Documentation, assignment in expression. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-03-26 05:36 +0000
          Re: Documentation, assignment in expression. Terry Reedy <tjreedy@udel.edu> - 2012-03-26 12:00 -0400
        Re: Documentation, assignment in expression. Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-03-26 15:59 +0200
          Re: Documentation, assignment in expression. Tim Chase <python.list@tim.thechases.com> - 2012-03-26 12:42 -0500
      Re: Documentation, assignment in expression. Chris Angelico <rosuav@gmail.com> - 2012-03-26 00:11 +1100
      Re: Documentation, assignment in expression. Tim Chase <python.list@tim.thechases.com> - 2012-03-25 08:48 -0500
        Re: Documentation, assignment in expression. Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-25 17:16 +0200
          Re: Documentation, assignment in expression. Tim Chase <python.list@tim.thechases.com> - 2012-03-25 13:22 -0500
          Re: Documentation, assignment in expression. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-03-26 05:47 +0000
          Re: Documentation, assignment in expression. Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-03-26 04:52 -0400
            Re: Documentation, assignment in expression. Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-26 12:56 +0200
              Re: Documentation, assignment in expression. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-03-26 14:13 +0300
                Re: Documentation, assignment in expression. Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-26 13:58 +0200
        Re: Documentation, assignment in expression. rusi <rustompmody@gmail.com> - 2012-03-25 09:17 -0700
        Re: Documentation, assignment in expression. mwilson@the-wire.com - 2012-03-25 19:09 -0400
          Re: Documentation, assignment in expression. Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-03-25 22:29 -0400
            Re: Documentation, assignment in expression. mwilson@the-wire.com - 2012-03-26 07:27 -0400
      Re: Documentation, assignment in expression. Chris Angelico <rosuav@gmail.com> - 2012-03-26 01:11 +1100
        Re: Documentation, assignment in expression. Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-25 17:17 +0200
      Re: Documentation, assignment in expression. Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-03-25 18:59 -0400
        Re: Documentation, assignment in expression. Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-03-26 15:54 +0200
          Re: Documentation, assignment in expression. Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-03-26 12:16 -0400
      Re: Documentation, assignment in expression. Tim Chase <python.list@tim.thechases.com> - 2012-03-26 05:14 -0500
  Re: Documentation, assignment in expression. Roy Smith <roy@panix.com> - 2012-03-23 21:37 -0400

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