[DB-SIG] PEP249 - Proposed change to DB-API 2.0

[chris@onca.catsden.net]

Okay, if I understand correctly, there's more support for adding in
'optional' support for 'optionally' supporting more than one paramstyle.
Ie, in the next version of the DB-API, we could add:

----

In addition to the above 'required' interface, the Python API implementer
may choose to offer the following interface:

   - include interface changes from my earlier post here -

----

Then, the /user/ of the API would have to check to see if the facilities
are available (ie, the presence of valid_paramstyles and set_paramstyle)
before attempting to use them.

My suggestion was to /require/ of a API implementor, if they want to make
their API compliant with DB-API 2.1 (or whatever we call it), to supply
the above interfaces, even if the only thing she does is to have a single
entry inside valid_paramstyles, and passing 'set_paramstyle' always throws
an exception if any other paramstyle is chosen.

I can see pros and cons on both sides:

Extension is Optional
---------------------

Pro: Very easy for the API implementor
Con: API user needs to write extra code to check
Pro: No problems caused if a 2.0 API is given to a 2.1 aware database APP

Extension is Required, even if Minimimally Implemented
------------------------------------------------------

Con: Many API's need to be modified to be 2.1 compliant (but the change is
trivial)
Pro: Less code change in the applications, unless you consder the code
change they'd go through to utilise the extension.


Given the above, I'd say that I too would support a 'optional'
implementation. Although, we do need to specifiy the requirements if any
API writer wants to implement this facility. Ie, "This is optional, but
if you do it, you must do it like this".




   ("`-/")_.-'"``-._        Ch'marr, a.k.a.
    . . `; -._    )-;-,_`)  Chris Cogdon <chmarr@furry.org.au>
   (v_,)'  _  )`-.\  ``-'
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