yii\db\Query::limit() function not limiting the records - Yii2

Question

Below is the code I'm using to get data from my table(s) for creating REST api.

$query = new yii\db\Query();
$sql = $query
    ->select('a.vehicle_number, b.device_id, b.dated, b.speed, b.ignition, b.latitude, b.longitude')
    ->from('tk103_devices a, tk103_current_location b')
    ->where('a.device_id = b.device_id AND a.transporter_id='.$id)
    ->orderBy(['a.vehicle_number'=>SORT_ASC])
    ->limit(1);

$dataProvider = new ActiveDataProvider([
    'query'=>$sql
    ]);
return array('count_flag'=>$countFlag, 'dataProvider'=>$dataProvider->getModels());

I had set the limit(1) which does " Sets the LIMIT part of the query. " as per Yii official doc http://www.yiiframework.com/doc-2.0/yii-db-querytrait.html#limit()-detail .

When I am executing the above query, all the records are being returned by the dataprovider.

What's wrong with my code?

Answer 1

ActiveDataProvider does not take care at query limit.

http://www.yiiframework.com/doc-2.0/guide-output-data-providers.html#active-data-provider

Extract from above link:

Note: If a query already specifies the orderBy clause, the new ordering instructions given by end users (through the sort configuration) will be appended to the existing orderBy clause. Any existing limit and offset clauses will be overwritten by the pagination request from end users (through the pagination configuration).

So, since you have fixed data, use ArrayDataProvider:

$data = $query
    ->select('a.vehicle_number, b.device_id, b.dated, b.speed, b.ignition, b.latitude, b.longitude')
    ->from('tk103_devices a, tk103_current_location b')
    ->where('a.device_id = b.device_id AND a.transporter_id='.$id)
    ->orderBy(['a.vehicle_number'=>SORT_ASC])
    ->limit(1)
    ->all();

$dataProvider = new \yii\data\ArrayDataProvider(['allModels' => $data]);

Answer 2

Did some homework by myself, I find solution to the above problem by changing the code as below:

$query = new yii\db\Query();
$sql = $query
    ->select('a.vehicle_number, b.device_id, b.dated, b.speed, b.ignition, b.latitude, b.longitude')
    ->from('tk103_devices a, tk103_current_location b')
    ->where('a.device_id = b.device_id AND a.transporter_id='.$id)
    ->orderBy(['a.vehicle_number'=>SORT_ASC])
    ->one();

$dataProvider = new ActiveDataProvider([
    'query'=>$sql
    ]);
return array('count_flag'=>$countFlag, 'dataProvider'=>$dataProvider);

As per my scenario, I wanted to retrieve only first record. So, I used one() instead of limit(1) .

Secondly, I was returning dataProvider as $dataProvider->getModels() . I changed this to $dataProvider only. Since "ActiveDataProvider does not take care at query limit." as per Fabrizio Caldarelli 's answer below (or) above, it was returning all retrieved records.

Hope that helps someone having related issues.

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For previous code to work, you must see Fabrizio Caldarelli 's answer below (or) above.