Re: [SQLObject] DBAPI prepared queries

[Ian B. <ia...@co...>]

Oleg Broytmann wrote:
> Hello!
> 
>    I have started a new "DBAPI prepared queries" branch at

Great!

> svn://colorstudy.com/home/phd/SQLObject/paramstyles
> 
>    The directory is called "paramstyles" because the implementation is
> based on http://cvs.sourceforge.net/viewcvs.py/*checkout*/ppa/misc/DBSingleStyle.py
> written by Denis Otkidach.

OK, so that's the 
list-with-special-objects-to-represent-bound-parameters style.  That 
seems fine -- it makes composition relatively straight-forward anyway 
(just using +).

>    Highlights of the last commit:
> 
> -- the return of the submodule sqlobject.include - there I put a copy of
>    DBSingleStyle.py;

In practice I think we'll need to maintain this module ourselves, and 
should feel free to fiddle with it as necessary.  I think.  Anyway, I 
don't know if we need to mark it as special (but it doesn't matter that 
much if we do).

> -- DBAPI._executeRetry() method is modified to allow query to be a string
>    (for backward compatibility) or sqlbuilder.SQLQuery instance.
> 
>    The branch requires developers to start working on it! All, or at least
> most occurrence of generated query strings must be changed to SQLQuery.
> Especially sqlbuilder.py requires work.

Unfortunately I'm heading out of town for this week and next, so I won't 
be able to help for a while.

Some thoughts:

* The current style has to continue to be supported, particularly things 
like "name = %s" % self.sqlrepr(value).  If all goes well, we can start 
emiting warnings in 0.9 (but I don't think 0.8 should emit warnings by 
default).

* We should maintain (or even expand) the introspectability of queries. 
  In the future we still want to be able to do things like automatically 
add joining clauses.  And coercing values in column-specific ways.  So 
for the most part the sqlbuilder model of specific query objects should 
be maintained, and instead something *like* __sqlrepr__ should be added 
(but not actually __sqlrepr__, since that's taken) that returns these 
special lists.  __sqllist__?  The to_* functions themselves could be 
extended to look for that attribute on objects, and if found they should 
call that function and expand as necessary.  Or a wrapper function or 
somesuch.

-- 
Ian Bicking  /  ia...@co...  /  http://blog.ianbicking.org