[Yii Framework] About the MANY_MANY

Let say we have three table as:

 

product:
  id;
  name;
category:
  id;
  name;
category_product:
  category_id;
  product_id;

 

 

From their structure we can know that product table and category table are MANY_MANY relation, category_product is the middle table, then how can we get the product records when we have a category.id? 

 

Set the models

Product: 

 代码

class Product extends CActiveRecord
{
    
//other codes
    public function relations()
    {
        
// NOTE: you may need to adjust the relation name and the related
        // class name for the relations automatically generated below.

        return array(
            
'categories'=>array(
                self
::MANY_MANY,
                
'Category',
                
'category_product(category_id, product_id)'
            )
,
            
'category_product'=>array(
                self
::HAS_MANY,
                
'CategoryProduct',
                
'product_id'
            )
,
        );
    }
    
//other codes
}

 

 Category:

代码
class Category extends CActiveRecord
{
    
//other codes
    public function relations()
    {

        return array(
            
'products'=>array(
                self
::MANY_MANY,
                
'Product',
                
'category_product(category_id, product_id)',
            )
,
            
'category_product'=>array(
                self
::HAS_MANY,
                
'CategoryProduct',
                
'category_id',
            )
,
        );
    }
    
//other codes
}

 

 

 CategoryProduct:

代码
class CategoryProduct extends CActiveRecord
{
    
//other codes
    public function relations()
    {
        
return array(
            
'category'=>array(
                self
::BELONGS_TO,
                
'Category',
                
'category_id',
            )
,
            
'product'=>array(
                self
::BELONGS_TO,
                
'Product',
                
'product_id',
            )
,
        );
    }
    
//other codes
}

 

 

 

Ok, let's show how to get the records in a controller!

代码
Class ProductController extends ActiveRecord
{
    
public function actionIndex()
    {
        
$dataProvider=new CActiveDataProvider(
            
'Product',
            
array(
                
'criteria'=>array(
                    
'with'=>array('category_product'),
                    
'condition'=>'display=1 AND category_product.category_id=1',
                    
'order'=>'t.id DESC',
                    
'together'=>true,
                )
,
            )
        );
        
$this->render('index',array(
            
'dataProvider'=>$dataProvider,
        ));
    }

 

Please pay attention to the property "together", we have to set it to true, otherwise, we will get error, of course, you can have a try. :)

 

By the way, we can also get the records with these codes without setting the rules in models!

代码
$dataProvider=new CActiveDataProvider(
            
'Product',
            
array(
                
'criteria'=>array(
                    
'condition'=>'display=1 AND cp.category_id='.$_GET['cat'],
                    
'order'=>'t.id DESC',
                    
'join'=>'LEFT JOIN category_product cp ON cp.product_id = t.id',
                )
,
            )
        );

 

Now we have another scene, we have a productID from the request, and we want to get all the same category products of this productID, let's check these code:

代码
$criteria = new CDbCriteria;
$criteria->with = array('category_product');
$criteria->condition = 'category_id in (select category_id from category_product where product_id = 1)';
$criteria->together = true;
$models = Product::model()->findAll($criteria);

 

 

 

 

Have fun with Yii! 

 

posted @ 2010-12-11 19:22 DavidHHuan 阅读(...) 评论(...) 编辑 收藏