Re: What is the best practice for adding persistence to an MVC model?

It sounds like you need a combination of MVC and the 3 Tier Architecture. They are not the same thing, for reasons described at http://www.tonymarston.net/php-mysql/infrastructure-faq.html#faq26 I have combined both these patterns in the Radicore framework - take a look at http://www.radicore.org/. If you don't like the idea of downloading a large framework there is a small sample application described in http://www.tonymarston.net/php-mysql/sample-application.html which is available for download. Basically you need to have code in every business object (every object in the Business layer) which communicates with a separate object for all its database access. This is known as a Data Access Object as it exists in the Data Access layer. If you do it right it will be possible to have a separate DAO for each DBMS so that you can switch between one database engine and another by simply changing a single configuration variable. In my own framework I have implemented DAOs for MySQL, PostgreSQL and Oracle. -- Tony Marston http://www.tonymarston.net http://www.radicore.org "Eric Bauman" <baumane@livejournal.dk> wrote in message news:B9.45.36627.EB296EA4@pb1.pair.com... > I'm in the process of implementing an ultra-light MVC framework in PHP. It > seems to be a common opinion that the loading of data from a database, > file etc. should be independent of the Model, and I agree. What I'm unsure > of is the best way to link this "data layer" into MVC. > > I've considered a few options: > > *Datastore interacts with Model* > > //controller > public function update() > { > > $model = $this->loadModel('foo'); > $data = $this->loadDataStore('foo', $model); > > $data->loadBar(9); //loads data and populates Model > $model->setBar('bar'); > $data->save(); //reads data from Model and saves > > } > > *Controller mediates between Model and Datastore* > > Seems a bit verbose and requires the model to know that a datastore > exists. > > //controller > public function update() > { > > $model = $this->loadModel('foo'); > $data = $this->loadDataStore('foo'); > > $model->setDataStore($data); > > $model->getDataStore->loadBar(9); //loads data and populates Model > $model->setBar('bar'); > $model->getDataStore->save(); //reads data from Model and saves > > } > > *Datastore extends Model* > > What happens if we want to save a Model extending a database datastore to > a flatfile datastore? > > //controller > public function update() > { > > $model = $this->loadHybrid('foo'); //get_class == Datastore_Database > > $model->loadBar(9); //loads data and populates > $model->setBar('bar'); > $model->save(); //saves > > } > > *Model extends datastore* > > This allows for Model portability, but it seems wrong to extend like this. > Further, the datastore cannot make use of any of the Model's methods. > > //controller extends model > public function update() > { > > $model = $this->loadHybrid('foo'); //get_class == Model > > $model->loadBar(9); //loads data and populates > $model->setBar('bar'); > $model->save(); //saves > > } > > > > Any input on the "best" option - or alternative - would be most > appreciated.