Chris Clark wrote: > M.-A. Lemburg wrote: >> Daniele Varrazzo wrote: >> >>>> On Jul 19, 2011 3:44 AM, "Federico Di Gregorio" >>>> <federico.digrego...@dndg.it> wrote: >>>> >>>>> At least 2 drivers (psycopg and pysqlite) provide a Python->backend >>>>> mechanism based on PEP 246, "Object Adaptation". If other implementors >>>>> are interested I can write a short explanation about how it works and >>>>> why it was chosen only for the Python->backend path and not for the >>>>> reverse. >>>>> >>> On Tue, Jul 19, 2011 at 11:05 AM, Vernon Cole <vernondc...@gmail.com> >>> wrote: >>> >>>> Yes, please. I would like to see that. Adodbapi has an output >>>> conversion >>>> mechanism, but I don't like it particularly well. >>>> >>> For a description: >>> >>> http://initd.org/psycopg/docs/advanced.html#adapting-new-python-types-to-sql-syntax >>> >>> http://initd.org/psycopg/docs/advanced.html#type-casting-of-sql-types-into-python-objects >>> >>> >> >> While this is a nice system, it's also very slow. It uses function >> calls and string parsing/conversion for adapting each value. This >> works if you only have to insert/fetch a few rows, but won't be >> feasible for larger volumes. >> >> I think we need something more low-level, which tries to >> avoid (Python) function calls if possible, ..... > > I have to confess the only piece of pep-0246 I read was: > >> >> Rejection Notice >> >> I'm rejecting this PEP. Something much better is about to happen; >> it's too early to say exactly what, but it's not going to resemble >> the proposal in this PEP too closely so it's better to start a new >> PEP. GvR. >> > > Does anyone know what the "better" option was? The date on the pep is a > number of years ago.
Not that I'm aware off. Python has moved on to ABCs, which address part of the intended use in a different way (the outside objects have to implement the protocol and announce this using an ABC). The adapter pattern is still useful, though. I just think that we need to provide a way for database modules to implement such adapter in straight C (as well as in Python) rather than requiring a round-trip to Python in all cases. The sketch I drew up would allow for this. Most database modules use such C adapters in some form anyway, so these would just need to be refactored a little bit to make them available to the Python application, which should help with the adoption of the new techniques. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Jul 20 2011) >>> Python/Zope Consulting and Support ... http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ ________________________________________________________________________ ::: Try our new mxODBC.Connect Python Database Interface for free ! :::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ _______________________________________________ DB-SIG maillist - DB-SIG@python.org http://mail.python.org/mailman/listinfo/db-sig
