模型类的codeigniter实例 [英] codeigniter instance of model class

问题描述

我正在开发一个使用codeigniter的网站。现在，通常当你在codeigniter中使用一个类，你基本上使用它，就像它是一个静态类。例如，如果我引用一个名为user的模型，我将首先使用

加载它。

  $ this-& > model（'user'）; 
  

然后，我可以调用该用户类上的方法，例如

  $ this-> user-> make_sandwitch（'cheese'）; 
  

在我正在构建的应用程序中，我想有一个UserManagement类，

 <$ c $ 
 c> $ this-> usermanager-> by_id（3）; 
  

，这会返回用户模型的实例
最好的方法是什么？

解决方案

CI中的模型类不完全相同作为其他语法中的模型类。在大多数情况下，模型实际上是某种形式的纯对象与数据库层与其交互。另一方面，使用CI， Model 表示返回通用对象的数据库层接口（它们在某些方面类似于数组）。

所以，如果你想使你的Model返回的东西不是一个 stdClass ，你需要包装数据库调用。

所以，这里是我会做的：

创建一个包含您的模型类的user_model_helper：

  class User_model {
 private $ id; 
 
 public function __construct（stdClass $ val）
 {
 $ this-> id = $ val-> id; 
 / * ... * / 
 / * 
 CI提供的stdClass每个db列都有一个属性。 
因此，如果您有列id，first_name，last_name，
 db将返回的值将具有first_name，last_name和id属性。 
这里是你要做的事情。 
 * / 
} 
} 
  

在usermanager.php：

  class Usermanager extends CI_Model {
 public function __construct（）
 {
 / * whatever你以前有过; * / 
 $ CI =& get_instance（）; // use get_instance，it is less prone to failure 
 // in this context。 
 $ CI-> load-> helper（user_model_helper）; 
} 
 
 public function by_id（$ id）
 {
 $ q = $ this-> db-> from（'users'） - > where（'id'，$ id） - > limit（1） - > get（）; 
 return new User_model（$ q-> result（））; 
} 
} 
  

I'm developing a site with codeigniter. Now, normally when you use a class in codeigniter, you basically use it as if it were a static class. For example, if I head a model called 'user', I would first load it using

$this->load->model('user');

and than, I could invoke methods on that user class like

$this->user->make_sandwitch('cheese');

in the application that I'm building, I would like to have one UserManagement class, which uses a class called 'user'.

so that, for example I could

$this->usermanager->by_id(3);

and this would return an instance of the user model where the id is 3. What's the best way to do that?

解决方案

The model classes in CI are not quite the same thing as model classes in other syntax's. In most cases, models will actually be some form of plain object with a database layer which interacts with it. With CI, on the other hand, Model represents the database layer interface which returns generic objects (they're kinda like arrays in some ways). I know, I feel lied to too.

So, if you want to make your Model return something which is not a stdClass, you need to wrap the database call.

So, here's what I would do:

Create a user_model_helper which has your model class:

class User_model {
    private $id;

    public function __construct( stdClass $val )
    {
        $this->id = $val->id; 
        /* ... */
        /*
          The stdClass provided by CI will have one property per db column.
          So, if you have the columns id, first_name, last_name the value the 
          db will return will have a first_name, last_name, and id properties.
          Here is where you would do something with those.
        */
    }
}

In usermanager.php:

class Usermanager extends CI_Model {
     public function __construct()
     {
          /* whatever you had before; */
          $CI =& get_instance(); // use get_instance, it is less prone to failure
                                 // in this context.
          $CI->load->helper("user_model_helper");
     }

     public function by_id( $id )
     {
           $q = $this->db->from('users')->where('id', $id)->limit(1)->get();
           return new User_model( $q->result() );
     }
}

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