Crud - Show Hasone Relation In Gridview

Yii 2.0 General Discussions
1

Hi

I’ve got two models, eg A and B

B has a function called getA() that returns an \yii\db\ActiveRelation:




public function getA()

{

  return $this->hasOne(A::className(), ['id' => 'a_id']);

}

The B index action shows a standard GII GridView widget. But in one of the columns I want to show the name of A.

I’ve managed to get this working by defining a column:




'columns' => [

  ...

  array(

      'header' => 'A',

      'value' => function($value, $model, $index) {

        $a = A::find(['id' => $value->a]);

        return $a->name;

      },

  ),

  ...

],

This works, but I’m worried this executes way to many queries.

Is there an better way to display the name A in the gridview?

2

If you are worried about too many queries, I would suggest you change your [font="Courier New"]dataProvider[/font] itself (either use a DB View or a join query as source for your dataProvider and the search model).

3 



$model->A->name;

your query execute just once

because of cache

CMIIW

4

Not quite. This executes n number of queries, where n = number of results in the grid search.

To optimize this, you’ll need to eager load the related data in the search model.




$query = $model::find();

$query->with("a"); // eager load data

$dataProvider = new ActiveDataProvider([

    'query' => $query,

]);

This will result in 2 queries:




select * from b

select * from a where a_id in (1,2,3,etc)

There have actually been several topics on GridView, so I wrote a tutorial on processing related model data. If you want to go further with sorting and filtering, check it out here.

5

Excellent! Works perfect.

For completeness also the change to the view:




'columns' => [

  ...

  array(

      'header' => 'A',

      'value' => function($value, $model, $index) {

        return $a->B->name;

      },

  ),

  ...

],

Nice! I’ve bookmarked this page!

Thnx!

6

Nice examples… you could put it on the wiki.