<?php

namespace frontend\controllers;
use yii\web\controller;
use yii;
class DataController extends Controller{

public function actionIndex(){
    $db = new \yii\db\Connection([
    'dsn' => 'mysql:host=localhost;dbname=aaa',
     'username' => 'root',
     'password' => '',
    ]);

    $db->open();
    //查询
    $command = $db->createCommand('SELECT * FROM zhuce')->queryAll();
    //修改
    //$command = $db->createCommand("UPDATE zhuce SET uname='qweqdqdq' WHERE id=2")->execute();
   	//删除
   	//$command = $db->createCommand("delete from zhuce where id =2")->execute();
   	//添加
   	//$command = $db->createCommand("insert into zhuce (uname,pwd)values('ok','123')")->execute();
   	//添加多条
   	//$command = $db->createCommand()->batchInsert('zhuce', ['uname', 'pwd'], [['Tom', 30],['Jane', 20],['Linda', 25]])->execute();
$session = Yii::$app->session;

}

}

?>

文件上传 多文件

`控制器
 yii\web\UploadedFile;
 $model->file = UploadedFile::getInstances($model, 'file');
        $file_arr = array();
        foreach($model -> file as $file){
            $file_name = 'uploads/' . time() . rand(111111,999999).'.'. $file->extension;
            $file -> saveAs($file_name);
            $file_arr[] = $file_name;
        }
 视图:
<?php
 use yii\widgets\ActiveForm;
 use yii\helpers\Html;
?>
 <?php $form=ActiveForm::begin(['options'=>['enctype'=>'multipart/form-data'],'action'=>   ['news/upfile'],'method'=>'post',])?>
 <?=$form->field($model,'file[]')->fileInput(['multiple'=>true])?>
 <?php echo Html::submitButton('提交',['class' => 'btn btn-primary'])?>
<?php ActiveForm::end();?>

`

        ```
 首先引入
           yii\data\Pagination;
           还有各种模型
        控制器:
            new一个AR对象出来
            $search = Yii::$app->request->get('search_key');
            $where = '1 = 1';
                if ($search) {
                    $where .= ' and JName like "%'.$search.'%"';
                }
                $pageArr = $model -> find()->where($where);
                $pagination = new Pagination(['totalCount' => $pageArr -> count(),'pageSize'=>'3']);
                $result = $pageArr ->join('INNER JOIN', 'recruit_enterprise','recruit_enterprise.CId = recruit_job.CId')
                                   ->select('*')
                                   ->offset($pagination ->offset)
                                   ->limit($pagination ->limit)
                                   ->where($where)
                                   ->asArray()
                                   ->all();

                return $this -> render('job_list',
                    ['result' => $result,
                    'pagination' => $pagination,
                    ]
                );

      以上是本人个人代码    仅供参考