Comparison of methods for finding specified fields using findfindAll in the Yii framework-PHP Tutorial-php.cn

Comparison of methods for finding specified fields using findfindAll in the Yii framework

高洛峰

Release： 2023-03-05 08:00:01

Original

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As we all know

modelName::model() -> find()　 //What is found is an object
modelName::model() -> findALL()　 //What is found It is an array of object collections
How to find the data of the fields I need, not the data of all fields

I did this before

$criteria = new CDbCriteria;
$criteria->select = &#39;username,id,email&#39;;
$criteria->order = &#39;id DESC&#39;;
$users = modelName::model()->findAll( $criteria );

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Backstage I accidentally saw someone else writing something like this, and realized how ignorant I was

$users = modelName::model()->findAll(array(
  &#39;select&#39; =>array(&#39;username&#39;,&#39;id&#39;,&#39;email&#39;),
  &#39;order&#39; => &#39;id DESC&#39;,
));

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After testing, I found that it really works, so find can also operate like this

$user = modelName::model()->find(array(
  &#39;select&#39; =>array(&#39;username&#39;,&#39;id&#39;,&#39;email&#39;),
  &#39;order&#39; => &#39;id DESC&#39;,
  &#39;condition&#39; => &#39;id=&#39;.$id,
));

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Of course, it is definitely not safe to do this. It can be replaced by the following method.

$users = $this->user->find(array(
  &#39;select&#39;=>array(&#39;id&#39;,&#39;username&#39;,&#39;email&#39;),
  &#39;order&#39; => &#39;id DESC&#39;,
  &#39;condition&#39; => &#39;state=:state AND id=:id&#39;,
  &#39;params&#39; => array(&#39;:state&#39;=>&#39;1&#39;,&#39;:id&#39; => &#39;2&#39;),
));

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Similarly, it can also be tested with findAll. Conclusion

This method can easily obtain the required data. Of course, when paging is required, new is required for the following CDbCriteria.

For example, I want to take out the 'v_id', 'title' in the videoinfo table, 'big_class', 'sub_class', 'upload_time', 'comment_num' and other fields, and the condition is status=1, follow lastmodifytime in reverse order, and only take out 3, do this:

$criteria = new CDbCriteria() ;
$criteria -> select = array(&#39;v_id&#39;,&#39;title&#39;,&#39;big_class&#39;,&#39;sub_class&#39;,&#39;upload_time&#39;,&#39;comment_num&#39;);    
$criteria -> condition = &#39;status = 1&#39;;
$criteria -> order = &#39;lastmodifytime desc&#39;;
$criteria -> limit = 3;
 $criteria ->params = array (&#39;:status&#39; => $你的变量) ;
$result = VideoInfo::model()->findAll($criteria);

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The line I commented out can be used to pass variables, represented by placeholders. For example, if your status needs to be conditionally assigned according to variables, you can assign a value in the commented line, and then write ## in the condition condition. #

$criteria -> condition = &#39;status = :status&#39;;

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That’s it,

In this way, the $result variable is the result you obtained. It is a list of objects and needs to be traversed:

foreach ($result as $ob){
      print_r($ob->attributes);
 }

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For example, if you want to display each field, just type

$ob->attributes[&#39;title&#39;];

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and so on.

is finished. The CPagination class can be used together with the CDbCriteria class and the front-end paging plug-in. Supports paging:

$count =VideoInfo::model()->count($criteria)
 
$pages=new CPagination($count);   
$pages->pageSize=30; //每页分多少条
$pages->applyLimit($criteria);

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$result = VideoInfo::model()->findAll($criteria);

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For more comparisons of methods of findfindAll to find specified fields in the Yii framework, please pay attention to the PHP Chinese website!