How to use CakePHP for client portfolio management application - php

Question

I understand the question title seems quite open-ended but I have already done a bit of reading/experimenting around the subject and have got somewhere with Cake in addition to building my own procedural-style app. My aim is to bring over my procedural app to CakePHP.
What the App does (or wants to do)
So, I have a bunch of clients, each client has 1 or more accounts. Each account has holdings that whose value is stored for a specific date. Here's an example of the database structure
The idea is to have the standard CRUD pages for clients, accounts etc. But also to have more sophisticated pages, for example, to give a return history for a clients accounts along with portfolio statistics. (I have other tables with more info in them but for the sake of simplicity I have omitted them from this issue for the time being)
What I've done
So, having following the tutorials, I've made models for clients and accounts and managed to link (associate?) the clients and accounts tables in CakePHP. I've also made controllers and views that allow me to retrieve the clients and accounts and made index, view, edit views.
Here are my model classes:
//Client.php
class Client extends AppModel {
public $hasMany = 'Account';
}
//Account.php
class Account extends AppModel {
public $belongsTo = 'Client';
public $hasMany = 'Holding';
}
//Holding.php
class Holding extends AppModel {
public $belongsTo = 'Account';
}
What I did Before
Let's say I want to make a page that shows the portfolio return for a given client. What I did in my last (crude) app was just make a php file (portfolio.php). I would then query the database for sum of the client's holdings on each month-end using a raw SQL statement. Then I'd loop though the array of returns calculating the % change in value from one month to the next.
This data can then be presented in an html table and I could then even plot the values on a chart etc.
This is a simplistic example of course. This page/view would introduce other info like benchmark comparisons (via another database table), stats like Sharpe ratio, vol, annualized return etc.
My question
How would similar functionality to the last section be implemented in CakePHP? It doesn't seem the view/page I'm after fits into the MVC ideology. Where would the logic involved in doing calculations go (e.g. calculating returns from the array of values)?
If I could have an explanation of how this kind of thing is implemented in MVC/CakePHP it would be really helpful.
The blog tutorial makes loads of sense but I can't yet see how it would extend to more complex applications.

Answer 1

CakePHP as a framework lets you quite free of where you put your logic. It tells you where you should make your DB call (models) and where you should control the flow of your app (controllers) but when it comes to behind the scene logic, the docs doesn't say much.
MVC as I understand it on the other hand is quite clear
Everything that treats data should go in the model.
Everything that deals with user interaction/flow control should go in the controller.
Everything that deals with user interface should go in the view.
Applied to CakePHP
That means most of your logic remains in the Models, and very few lays in the Controllers. It's also better this way since you can easily call $this->Model->foo() from any linked controller whereas calling a function defined in a another controller is hardly encouraged due to performance issue and is really not a good practice.
Other things you can investigate are Components and Behaviors.
Components are basically a set a functions that you want to share between controllers. It has more or less the same capabilities than the Controller but does not have dedicated routes, views or model.
Behaviors are the equivalent for the models, its good when you have several models that have similar behavior and you want to keep you code DRY.
Your case
In your particular case, I would go with small functions in models. For instance, all the functions that manipulates holdings information should be in the Holding model. It's nice because you can call these functions both from the Controller or another model, you could have a preparePortfolio() function in your User model that calls a few functions in the Holding model, do all kind of arrangement and then give back consolidated data to the UserController ready to be passed to the view.
One last thing
I highly recommend you have a look at the Hash class if you deal with arrays and loops. You can avoid looping through multidimensional array by using some of this functions and it can literally boost your performance if you deal with huge arrays. It has also a much cleaner syntax than having imbricated loops.
Code sample to help
app/Controller/ClientsController.php
<?php
App::uses( 'AppController', 'Controller' );
class ClientController extends AppController {
public function portfolio( $clientId ) {
$this->Client->id = $clientId;
if( !$this->Client->exists() ) {
throw new NotFoundException( 'There are no client with this id' );
}
$data = $this->Client->portfolio( $clientId );
$this->set( compact( 'data' ) );
}
}
app/Model/Client.php
<?php
App::uses( 'AppModel', 'Model' );
class Client extends AppModel {
public $hasMany = array(
'Account' => array(
'className' => 'Account',
'foreignKey' => 'client_id'
)
);
public function portfolio( $clientId ) {
$holdings = $this->Account->Holding->find( 'all', $findParameters );
$foo = $this->Account->Holding->doThings( $holdings );
return $foo;
}
}
app/Model/Account.php
<?php
App::uses( 'AppModel', 'Model' );
class Account extends AppModel {
public $hasMany = array(
'Holding' => array(
'className' => 'Holding',
'foreignKey' => 'account_id'
)
);
public $belongsTo = array(
'Client' => array(
'className' => 'Client',
'foreignKey' => 'client_id'
)
);
}
app/Model/Holding.php
<?php
App::uses( 'AppModel', 'Model' );
class Holding extends AppModel {
public $belongsTo = array(
'Account' => array(
'className' => 'Account',
'foreignKey' => 'account_id'
)
);
public function doThings( $holdings ) {
foreach( $holdings as $key => $value ) {
// code...
}
return $bar;
}
}