python-sybase-misc

[Python-sybase-misc] Regression in 0.39 Connection().execute()

[Bond, G. <Gre...@it...>]

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Re: [Python-sybase-misc] Regression in 0.39 Connection().execute()

[Sébastien S. <sa...@us...>]

[Replying to all]

Hi Gregory,

sorry for the late reply, I have been very busy at work.

I will correct this bug for python-sybase 0.40 which should be released 
before the end of the year. I should be working nearly full time on 
python-sybase for the coming month.

You should note however that Connection.execute is deprecated so that 
you should probably plan to migrate to a cursor at some stage.

regards

-- 
Sébastien Sablé


Bond, Gregory a écrit :
> I’ve just added a bug for this: 
>  https://sourceforge.net/tracker/index.php?func=detail&aid=2165436&group_id=184050&atid=907701 
> <https://sourceforge.net/tracker/index.php?func=detail&aid=2165436&group_id=184050&atid=907701>
> 
> In previous versions (0.38 all the way back to 0.13!) we could do:
>     print db.execute('select 1,2,3')
>     [[(1, 2, 3)]]
> 
>     print db.execute('select 1,2,3 select 4,5')
>     [[(1, 2, 3)], [(4, 5)]]
> 
> In 0.39, execute() now uses a cursor under the hood and returns None. 
>  The use of a cursor means no multiple select statements :
>     print db.execute('select 1,2,3')
>     None
> 
>     print db.execute('select 1,2,3 select 4,5')
>     Traceback (most recent call last):
>         .....
>     Sybase.DatabaseError: Msg 3804, Level 16, State 1, Line 1
>     More than one SELECT statement is used to define the cursor 
> 'ctmp823fd0c'.
> 
> We depend fairly heavily on both behaviours (returning resultsets, 
> taking multiple select statements).
> 
> I’ve worked out a way to support /most/ of the old behaviour, with some 
> ugly hackery that looks inside Cursor objects (see the bug above), but 
> it’s not perfect.   The last remaining problem is multiple selects – it 
> mashes all the resultsets into one:
> 
>     print db.execute('select 1,2,3 select 4,5')
>     [[(1, 2, 3), (4, 5)]]
> 
> Any clues how to handle this?  Is this behaviour something that was 
> deliberately removed or would “we” be willing to patch this, if we can 
> come up with a method?
> 
> -- 
> *Gregory Bond
> Vice President
> Product Manager, Middle & Back Office Systems
> ITG Australia Limited
> Investment Technology Group, Inc.
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> Level 3, Rialto North Tower
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> Fax: +61 3 9211 2599
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> www.itg.com
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> 
> The information contained in this email is believed to be accurate at the time of publication.  However, ITG disclaims all responsibility for any loss or damage howsoever arising as a result of any person or entity acting upon the information contained in this email and no liability will be accepted by ITG for any such loss or damage.  Any views expressed in this email are those of the individual sender, except where the email states otherwise and the sender is authorized to state them to be the views of ITG.
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Re: [Python-sybase-misc] Regression in 0.39 Connection().execute()

[Andrew M. <an...@ob...>]

>You should note however that Connection.execute is deprecated so that 
>you should probably plan to migrate to a cursor at some stage.

When I was working on my PostgreSQL adapter (ocpgdb), I initially added
a Connection.execute before I had implemented the Cursor logic, intending
to remove it when done. However, there are SQL statements that PostgreSQL
will not execute within a cursor which necessitates some mechanism for
sending commands not within a cursor. A Connection.execute method seems
like the most natural answer to me, so I've left it in. It's also quite
a bit faster for some operations, as it requires considerably less round
trips to the server.

-- 
Andrew McNamara, Senior Developer, Object Craft
http://www.object-craft.com.au/