[Grok-dev] Grok with existing SQLAlchemy mapped classes

Wyatt Baldwin wyatt.lee.baldwin at gmail.com
Thu Jul 23 17:18:34 EDT 2009

On Thu, Jul 23, 2009 at 2:03 PM, Santiago
Videla<santiago.videla at gmail.com> wrote:
> Hey,
> On Thu, Jul 23, 2009 at 3:40 PM, Wyatt Baldwin <wyatt.lee.baldwin at gmail.com>
> wrote:
>> I have an existing Web application written in Python that I'm looking to
>> re-implement in a modern Python framework. Now that Grok is approaching 1.0,
>> I am taking another look at it for this purpose, and it's lookin' good.
>> My only question (at this point, anyway) is whether there is a way to
>> reuse existing SQLAlchemy-based model classes without having to add any Grok
>> directives and/or Zope-specific integration code to them. The model for my
>> application is in a "core" package that *cannot* be modified to support Grok
>> (or any other Web framework) directly. One idea I have is a function that
>> takes a SA mapped class and returns a Grok model.
>> I've started looking at some of the libraries for integrating SA with
>> Zope/Grok, but I admit that I haven't looked very deeply as yet. I've also
>> been reading the Grok docs and this list but haven't found a definite answer
>> yet. Is what I want to do already possible? Would it be straightforward to
>> implement something like an `sa_model_wrapper`? Can I create a subclass of a
>> SA model class that uses `grok.Model` as a mixin?
> You may want to checkout megrok.rdb [1] but I'm not sure if it's what you
> are looking for.

I took a look at megrok.rdb, but from what I can gather (from the
README), I'd have to create my model classes with an rdb.Model base
class and then use some rdb directives to set up the metadata. The
problem is, I want my models to stand alone and only depend on
SQLAlchemy so they can be reused with other frameworks or in desktop

> Take a look to the doctest of reflection [2], I didn't try it my self, but
> it seems that you are able to define Grok models that will be mapped to
> existing tables.

I'll take a look.



> [1] http://svn.zope.org/megrok.rdb/
> [2] http://svn.zope.org/megrok.rdb/trunk/src/megrok/rdb/tests/reflection.py

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