what is CakePHP model alias used for?

Question

In user model:

var $hasMany = array(
        \'Photo\' => array(
            \'className\' => \'Photo\',
            \'foreignKey\' => \'owner_id\',         


        

Answer 1

Two useful scenarios for aliases:

1. Multiple foreign keys to the same model

For example, your photos table has two fields: created_user_id & modified_user_id

var $belongsTo = array(
    'CreatedUser' => array(
        'className' => 'User',
        'foreignKey' => 'created_user_id',
        ...
    ),
    'ModifiedUser' => array(
        'className' => 'User',
        'foreignKey' => 'modified_user_id',
        ...
    ),
);

2. Creating logical words specific to your application's domain

Using the conditions field in the array, you could specify different kinds of models:

var $hasMany = array(
    'ApprovedUser' => array(
        'className' => 'User',
        'foreignKey' => 'group_id',
        'conditions' => array(
            'User.approved' => 1,
            'User.deleted'  => 0
        ),
        ...
    ),
    'UnapprovedUser' => array(
        'className' => 'User',
        'foreignKey' => 'group_id',
        'conditions' => array(
            'User.approved' => 0,
            'User.deleted'  => 0
        ),
        ...
    ),
    'DeletedUser' => array(
        'className' => 'User',
        'foreignKey' => 'group_id',
        'conditions' => array('User.deleted'  => 1),
        ...
    ),
);

In the above example, a Group model has different kinds of users (approved, unapproved and deleted). Using aliases helps make your code very elegant.

Answer 2

It allows you to do things like $this->Owner->read(null,$userId); You can have an OwnersController and views/owners.

It is ... an alias. In a sense, User is an alias for the db table users.

A better example: I have a CMS where I use the table articles for Article, BlogItem and News. Those three names are aliases for the same table that allow me to set up different models, relationships and behaviour. So I have a BlogItemsController and a NewsController as well as an ArticlesController.