Thinkphp 视图模型

class BlogViewModel extends ViewModel {
   public $viewFields = array(
     ‘Blog‘=>array(‘id‘,‘name‘,‘title‘),
     ‘Category‘=>array(‘title‘=>‘category_name‘,‘_on‘=>‘Category.id=Blog.category_id‘,‘_type‘=>‘RIGHT‘),
     ‘User‘=>array(‘name‘=>‘username‘, ‘_on‘=>‘Blog.user_id=User.id‘),
   );
 }

Select 
 Blog.id as id,
 Blog.name as name,
 Blog.title as title,

 Category.title as category_name,

 User.name as username 

 from think_blog Blog JOIN think_category Category JOIN think_user User 
 where Blog.category_id=Category.id AND Blog.user_id=User.id