Best way to load models in CakePHP 2.0

问题:

I'm not sure of the best way to load models in CakePHP 2.0 now.

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Question 1

I have a model where more than one database field is related to another model.

customers table has the fields country_origin, country_residence and country_study and all of those fields contain an ID from the table countries.

So in my Customer model, how am I supposed to load the Country model?

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Question 2

Has Controller::loadModel() been deprecated or is it bad practice to use this? How am I supposed to load a model in the controller?

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Question 3

When or why do you have to use App::uses() in a controller or model? I don't understand the point when the models will load anyway if you use the normal methods like loadModel(), hasOne, hasMany, belongsTo, etc.

回答1:

This should be simple to understand. If you are using a controller and you need to load another model, you can call:

$this->loadModel('SomeModel');

Then you can make calls to the model like you normally would:

$this->SomeModel->read(null, '1');

App::uses is for lazy loading of classes. So you can still load a model using uses:

App::uses('MyModel', 'Model');

But then you will need to call it differently:

$MyModel = new MyModel();
$MyModel->read(null, '1');

or

MyModel::read(null, '1');

It just depends on where and how you want to use it.

回答2:

The preferred way is

$this->load('MyModel');

However, you can also use

public $uses = array('DefaultModel', 'MyModel');
.
.
$this->MyModel->field(...);

Cake supports both and you are free to use anyone you like.

回答3:

For Question 1

As per your structure there is an association between Customer and Country model i think so we don't need to load model. We can create virtual association for each id such as,

 'CountryOrigin' => array(
  'className' => 'Country',
  'foreignKey' => 'country_origin_id',
  'dependent' => true,
  'conditions' => '',
  'fields' => '',
  'order' => '',
  'limit' => '',
  'offset' => '',
  'exclusive' => '',
  'finderQuery' => '',
  'counterQuery' => ''
)


'CountryResidence' => array(
  'className' => 'Country',
  'foreignKey' => 'country_residence_id',
  'dependent' => true,
  'conditions' => '',
  'fields' => '',
  'order' => '',
  'limit' => '',
  'offset' => '',
  'exclusive' => '',
  'finderQuery' => '',
  'counterQuery' => ''
)

By doing this we can create an association between models so we don't want to load model explicitly

Loading model is good when we don't have an association for that we can use as,

Syntax for load Model is For single model load

$this->loadModel('Country');

This will be more useful if we want to load model for particular action or condition

If we wan to use throughout the controller we can use $uses variable For multiple model load.

public $uses = array('Country','OtherModel');

we can access model like,

$this->Country->find('count');