[DB-SIG] cx_Oracle 2.5

[Anthony Tuininga]

On Wed, 2002-07-17 at 02:06, M.-A. Lemburg wrote:
> Anthony Tuininga wrote:
> > What is cx_Oracle?
> > 
> >  7) Implemented cursor method executemany() which expects a list of
> >     dictionaries for the arguments
> 
> As per DB API this should be a sequence of sequences. Dictionaries
> are not sequences.

The one problem with passing a list of sequences (lists or tuples) is
that it would mean that I would have to use bind by position in this
case when I am using bind by name in all other cases. That would seem to
me to be inconsistent with the execute() method which expects bind by
name, don't you think? To me, it would make more sense that execute()
and executemany() would use the same method of binding; otherwise, if I
want to use executemany() I have to completely change my SQL statement
and my bound variables!!? Comments?

> > 11) Added cursor method executemanyprepared() which is identical to
> the
> >     method executemany() except that it takes a single argument which
> is
> >     the number of times to execute a previously prepared statement and
> >     it assumes that the bind variables already have their values set;
> >     used for high performance only
> 
> Such a method is not needed if you implement the .execute()
> caching of commands as described in the DB API. .prepare()
> can also nicely hook into this scheme if you expose the prepared
> command:
> 
> c.prepare('stuff')
> c.executemany(c.command, list_of_data_tuples)

Not true. I support the following construct:

defined_vars = c1.execute(some_select_statement)
# insert code to transform defined_vars (sequence) to bind_vars
(dictionary)
c2.setinputsizes(bind_vars)
c2.prepare(some_insert_statement)
c1.fetchraw(num_rows)
c2.executemanyprepared(num_rows)

This code permits a straight copy from the fetch of one statement to the
input of another. Please keep in mind that this is intended __ONLY__ for
high performance code as the database API is more than adequate in terms
of features for handling this stuff -- it just performs at about half to
one third of the speed!

BTW, I do support the prepare() method but I always pass None to the
execute() method to indicate that the previously prepared statement
ought to be used, rather than passing c.command.

> -- 
> Marc-Andre Lemburg
> CEO eGenix.com Software GmbH
> _______________________________________________________________________
> eGenix.com -- Makers of the Python mx Extensions: mxDateTime,mxODBC,...
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-- 
Anthony Tuininga
anthony@computronix.com
 
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