[SQLObject] Re: problem: implementing BoolCol

[Nick <ni...@dd...>]

[ earlier discussion about implementing different SQL types and
  converting them to Python types ]

I've been looking at the code for Constraints and Col, and it looks to
me like there needs to be a distiction between real constraints
(MaxLength, Unique, Not Null, for example) and type checking/casting. 
It's a little mixed right now.  In terms of type checking and
conversion, I would propose:

1) make validators part of Col instead of just random functions in
Constraints that get referenced in Col.

2) at the rate it's going, there are going to be a lot of parallel
_mysql, _postgres, _sqlite, etc. functions for every operation under
Col.  There needs to be a way to bundle a bunch of functions for the
particular db api, probably related to whatever _connection type you're
using.

3) for each db api, there needs to be convert-from-result-to-python and
convert-from-python-to-sql-value functions as part of the Col class,
encapsulated by the mechanism described in 2.

I've got some ideas how to do this, but I don't want to go ripping
through the code if you're going somewhere else with this.

Nick