Feature request: DataProvider for related models

[alpharder]

Dear developers!
Yii lacked of this functionality, but in my opinion this is very basic thing which is very often needed. So much hope to see it at Yii2 release.

Suppose we have two entities: "Blog" and "Subscriber", their relations between each other are:

• Blog MANY_MANY Subscribers;
• Subscriber MANY_MANY Blog;

It is very easy to fetch all of the subscribers of concrete blog:

$subscribers= $blog->subscribers;

Problem:

But when we want to use pagination together with other charms of CListView or CGridView, the easiest way is CActiveDataProvider.

Currently available solution

In this case, we have to write monstrous piece of code every time:

$blog = Blog::model()->findByPk(1);

$dataProvider = new CActiveDataProvider(Subscriber::model(), array(
    'criteria' => array(
         'with'     => array(
                'blogs' => array(
                      'select' => false,
                      'joinType' => 'INNER JOIN',
                      'on'       => 'blogs.id = :currentBlogID',
                      'params'   => array(':currentBlogID' => $blog->id)
                 )
         ),
         'together' => true
)));

I think this could come as a part of framework, probably like this:

$blog = Blog::model()->findByPk(1);

$config = array('pagination'=>array('pageSize'=>20));

$dataProvider = CActiveDataProvider::createForRelation(
        array($blog, 'subscribers'),
        $config
);

I think this method could easily programmaticaly generate criteria of retrieving related records for both MANY_MANY and HAS_MANY relation types.
Unfortunately, I'm not very familiar with code of CActiveFinder and CJoinElement, but I'm pretty sure they do the same work while generating SQL for eager-loading of related records. So, probably, they can be used for this purpose.

[samdark]

There's no MANY_MANY in Yii2.

[alpharder]

Ooops. Ok, I have just read docs about new AR.
So, as I understood, the solution in Yii2 will be like:

class Order extends \yii\db\ActiveRecord
{
    public function getItems()
    {
        return $this->hasMany('Item', array('id' => 'item_id'))
            ->viaTable('tbl_order_item', array('order_id' => 'id'));
    }
}

// At controller:

$order = Order::find(1);

$itemsDataProvider = new ActiveDataProvider(array( 
        'query' => $order->getItems(),
        'pagination' => array( 'pageSize' => 20 )
));

Yes?

[samdark]

Yes. I haven't tried it with any real data yet so would be great if you'll do and confirm that it's OK.

[alpharder]

Looks fantastic. I'll try as soon as I have enough time and tell the results. Thanks!

[cebe]

This is exactly how it works. ;-)

[fatihah8811]

yes.. its works.. Many to many relationship between 3 table tbl_A, tbl_AB, tbl_B..
this is how we call it from our view file.. Lets share our code since there are lack of source regarding YII2.. Thanks.. =)

--- In Model A ---

public function getB(){
            `return $this->hasMany(B::className(), ['id' => 'B_id'])
                ->viaTable('tbl_AB', ['A_id' => 'id']);
    }

--- In Controller A ---

public function actionView($id)
    {
        $model = $this->findModel($id);
        $dataProviderB = new ActiveDataProvider([
            'query' => $model->getB(),
        ]);

        return $this->render('view', [
            'model' => $model,
            'dataProviderB'=>$dataProviderB,
        ]);
    }

--- In view.php A ---

GridView::widget([
        'dataProvider' => $dataProviderB,
        'columns' => [
            ['class' => 'yii\grid\SerialColumn'],

            'mod_nama',

            ['class' => 'yii\grid\ActionColumn'],
        ],
    ]);

[ajayvembu90]

Is this issue resolved by yii?

[cebe]

@ajayvembu90 yes.