Re: [cx-oracle-users] Help with fetchraw

[Chris D. <cdu...@ya...>]

See in-line
--- Anthony Tuininga <ant...@gm...> wrote:

> On 5/15/05, Leith Parkin <lei...@gm...> wrote:
> > Hi Chris,
> > 
> > This is a quick example i knocked togethor ages ago to return a dict
> > result set instead of tuples. In retrospect fetchall() would probably
> > be better writtern as a generator under the newer python stuff.
> 
> Definitely. :-) Especially if you wanted to use it for large result sets.
> 
> > eg r = db.fetchone()
> > r['FIELDNAME']
> > 
> > Prehaps Anthony could give some feedback as to the "correctness" of this.
> 
> Looks "correct" to me. It works, doesn't it?? :-) As suggested, if you
> wanted to override the __iter__() method (or the fetchall() as shown
> below) to replace None with "" for null strings, that would be quite
> doable. If you need an example of that, I could probably whip
> something up. As you can see by this example, subclassing to extend or
> override functionality is actually quite simple.

Anthony,

If you could supply a simple example that would be much appreciated.

Thanks,

Chris

> 
> > --- SNIP ---
> > from cx_Oracle import *
> > 
> > # DictCursor for Oracle, returns dicts instead of tuples
> > class DictConnect(Connection):
> >         def cursor(self):
> >                 return DictCursor(self)
> > 
> > class DictCursor(Cursor):
> >     def fetchall(self):
> >         r = Cursor.fetchall(self)
> >         result = []
> >         for l in r:
> >             result.append( dict([(a[0],b) for a,b in
> > zip(self.description, l)]) )
> > 
> >         return result
> > 
> >     def fetchone(self):
> >         r = Cursor.fetchone(self)
> >         if r:
> >                 return dict([(a[0],b) for a,b in zip(self.description, r)])
> >         else:
> >                 return None
> > 
> > # factory class
> > def connect(**kw):
> >         return DictConnect(**kw)
> > 
> > ---- SNIP ----
> > 
> > On 5/15/05, Chris Dunscombe <cdu...@ya...> wrote:
> > > Leith,
> > >
> > > Thanks, I like the sub-classing idea but my OO Python isn't that good so if you could give
> me a
> > > code example that would be much appreciated.
> > >
> > > Thanks very much,
> > >
> > > Chris
> > > --- Leith Parkin <lei...@gm...> wrote:
> > >
> > > > Hi Chris,
> > > >
> > > > No worries. We have a very similair setup at work, transferring
> > > > summarised data from oracle into MySQL.
> > > >
> > > > Depending on the database you are transferring too, couldnt you set a
> > > > trigger, inserting NULL (eg, a python None from Oracle) into the table
> > > > generates an empty string?
> > > >
> > > > Failing that, subclassing cx_Oracles cursor object to return a the
> > > > empty string when the column type is textual and the value is null
> > > > might be another option.
> > > >
> > > > Good luck,
> > > >
> > > > Leith
> > > >



		
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