psycopg2 or pygresql?

exhuma.twn exhuma at gmail.com
Wed Sep 19 18:24:37 CEST 2007


On Sep 19, 5:47 pm, Steve Holden <st... at holdenweb.com> wrote:
> exhuma.twn wrote:
> > Plain and simple. What would you use?
>
> > So far I have written everything with psycopg2. One thing that annoys
> > me is that I cannot easily access the column names from a query. I
> > know that this is not part of the DBAPI2  so I cannot expect the model
> > to suport it.
>
> Yes it is.
>
> Execute a SELECT * FROM TABLE WHERE 1=0 and then examine
> cursor.description. This allows you to introspect on database structure.
>
> > I quite like the "mogrify" method of psycopg2 very much. It's very
> > useful for debugging.
>
> > And before someone says: "Use the DictCursor-factory to access column
> > names". Yes I can do that. But a dict does not guarantee the same
> > order of keys as the columns were specified in the query.
>
> See below.
>
> > The reason: I wrote a very simple Qt-Widget (inherited from
> > QTableWidget) that takes a SQL query and displays the results. And I
> > would like to have the columns ordered the same way as I specified in
> > the query *with* a header-label. For now I hava a method on the widget
> > which takes a query, *and* a list of labels.
>
> > I can live with that though. Although it itches me.
>
> > Would pygresql solve my dilemma? Or would you rather say: "Don't use
> > pygresql!"  ;)
>
> Here's a psycopg2-based session:
>
>  >>> curs
> <cursor object at 0x00B823C8; closed: 0>
>  >>> curs.execute("SELECT * FROM Person WHERE 1=0")
>  >>> curs.description
> (('psnid', 23, None, 4, None, None, None), ('psnfirstname', 1043, None,
> 50, None, None, None), ('psnlastname', 1043, None, 50, None, None,
> None), ('psndear', 1043, None, 50, None, None, None), ('psntitle', 1043,
> None, 50, None, None, None), ('psnworkphone', 1043, None, 30, None,
> None, None), ('psnworkextension', 1043, None, 20, None, None, None),
> ('psnhomephone', 1043, None, 30, None, None, None), ('psnmobilephone',
> 1043, None, 30, None, None, None), ('psnfaxnumber', 1043, None, 30,
> None, None, None), ('psnemailname', 1043, None, 50, None, None, None),
> ('psnreferredby', 1043, None, 50, None, None, None), ('psnlocid', 23,
> None, 4, None, None, None), ('psnnotes', 1043, None, -1, None, None, None))
>
> I believe if you use specific column names in your query they will
> appear in the order given in the query also.
>
> I use this technique in
>
>    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/81189
>
> to print arbitrary query outputs.
>
> regards
>   Steve
> --
> Steve Holden        +1 571 484 6266   +1 800 494 3119
> Holden Web LLC/Ltd          http://www.holdenweb.com
> Skype: holdenweb      http://del.icio.us/steve.holden
>
> Sorry, the dog ate my .sigline


Apparently I am deaf dumb and blind.... :( Sorry. I grepped several
times through the PEP for various other reasons, and this little bit
escaped me.

Thanks for being nice guys and answering anyhow. Much appreciated.




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