sorry for the late replies of my side - bad setup of the group for
me.

IdentityMaps is wrong - my mistake.

nesting happens if you stack two or more of the IM over each other.

if IM works is a matter of trust ;-) as Chris said they are not
essentlial but nice to have.

- Kristian

On Jul 1, 7:41 pm, Bence <[email protected]> wrote:
> I tested Kristian's two lines, but it broke the ApplicationController
> with "uninitialized constant Rails::DataMapper::IdentityMaps" error.
> Maybe I'm doing something wrong...
>
> The standard "user Rails::DataMapper::Middleware:IdentityMap" and
> enforcing the :external repo through self.respository in the model
> works - I can access the model from the controller. I'm not certain,
> though, whether the IM is used in this case?
>
> Thanks again for your tips, guys! You helped me get over a frustrating
> bump!
>
> On Jul 1, 3:07 pm, Chris Corbyn <[email protected]> wrote:
>
>
>
>
>
>
>
> > They go inside ApplicationController, right inside the class body.
>
> > class ApplicationController < ActionController::Base
> >   use 'Rails::DataMapper::IdentityMaps', :external
> >   use 'Rails::DataMapper::IdentityMaps'
>
> >   ... rest of controller here ...
> > end
>
> > They're not essential, but that's what provides your identity map, so that 
> > when you fetch the same resource multiple times, you don't query the 
> > database repeatedly, and when that resource is changed, everybody sees the 
> > changes.
>
> > I have "use Rails::DataMapper::Middleware::IdentityMap" (singular) in my 
> > controller... I assume there is a pluralized version for when you're using 
> > multiple identity maps.  This is just what the dm-rails template configures 
> > though.
>
> > On 01/07/2011, at 22:59, Bence wrote:
>
> > > Thanks, Kristian!
>
> > > I meant the
> > >  use 'Rails::DataMapper::IdentityMaps', :external
> > >  use 'Rails::DataMapper::IdentityMaps'
> > > lines you wrote. Where do the go? They don't seem to work in
> > > ApplicationController just like that. I'm not certain how to set up
> > > nested identity maps, and have not found examples...
>
> > > /B
>
> > > On Jul 1, 5:30 am, kristian <[email protected]> wrote:
> > >> yes, the method I was talking about was in model.
>
> > >> now you are using no IdentiyMaps for the external repo and you can add
> > >> it by adding
> > >> "use Rails::..." in the ApplicationController. but make sure the order
> > >> is correct or use these #repository trick for ALL models.
>
> > >> - Kristian
>
> > >> On Jun 30, 3:56 pm, Bence <[email protected]> wrote:
>
> > >>> Thanks!
>
> > >>> I overrode the #repository as you described, and it seems to have done
> > >>> the trick. I did this in the model - I guess this is what you meant by
> > >>> "binding in a static way"?
>
> > >>> Where do the "use 'Rails::...'" lines go? Are they required? I'm not
> > >>> using them right now at all, and the repository seems to be the right
> > >>> one on my external model.
>
> > >>> //B
>
> > >>> On Jun 29, 6:56 am, kristian <[email protected]> wrote:
>
> > >>>> what I do on almost all my projects (datamapper makes it to easy to
> > >>>> use morethen one repo) is that I am using nested IdentityMaps one for
> > >>>> the default and one for the :external repository
>
> > >>>>   use 'Rails::DataMapper::IdentityMaps', :external
> > >>>>   use 'Rails::DataMapper::IdentityMaps'
>
> > >>>> in order to "dispatch" the models onto the right repository I am
> > >>>> overwrite this method
>
> > >>>>  def self.repository(name = nil, &block)
> > >>>>     super(:external, &block)
> > >>>>   end
>
> > >>>> so basically I bind the model to the :external repository in static
> > >>>> way. the same thing I do for transactions !
>
> > >>>> maybe that helps.
>
> > >>>> - Kristian
>
> > >>>> On Jun 29, 6:41 am, Chris Corbyn <[email protected]> wrote:
>
> > >>>>> Note that you can disable that "everything is wrapped in a repository 
> > >>>>> block" behaviour by removing this line from ApplicationController:
>
> > >>>>> use Rails::DataMapper::Middleware::IdentityMap
>
> > >>>>> You won't have an identity-map per-request if you do this though.
>
> > >>>>> On 28/06/2011, at 21:48, Bence wrote:
>
> > >>>>>> Hi,
>
> > >>>>>> I'm new to DataMapper and run into a confusing issue to which I 
> > >>>>>> didn't
> > >>>>>> find any answers.
>
> > >>>>>> I have two repositories (:default and :external).
> > >>>>>> Model "ext_model" is persisted in :external by setting the
> > >>>>>> default_repository_name in the model. The model works: the unit tests
> > >>>>>> are green and I can manipulate the model in the console without
> > >>>>>> problems.
> > >>>>>> When I run the unit tests on controller ext_model_controller#index, 
> > >>>>>> it
> > >>>>>> is green: retrieves all from ext_model, as it should.
> > >>>>>> But when I launch the webserver and browse to /ext_model_controller/
> > >>>>>> index, I get an error message, and I see that it is looking for
> > >>>>>> ext_model in the :default repository (instead of :external).
> > >>>>>> Shouldn't both the console and the server retrieve the model the same
> > >>>>>> way? Am I missing something? How do I set explicitly the repository 
> > >>>>>> on
> > >>>>>> the model so that the webserver uses that?
> > >>>>>> If I wrap the code inside ext_model_controller#index action in
> > >>>>>> DataMapper.repository(:external) {...} then it works, but shouldn't
> > >>>>>> this be unnecessary since I already explicitly assigned a repository
> > >>>>>> to the model?
>
> > >>>>>> Thanks in advance!
>
> > >>>>>> //Bence
>
> > >>>>>> Rails 3.0.9, dm 1.1.0
>
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