首先，先来看一下问题代码：

1、控制器代码如下：

    public function actionIndex()    {        $query = Country::find();         $pagination = new Pagination([            'defaultPageSize' => 5,            'totalCount' => $query->count()        ]);         $countries = $query->orderBy('name')            ->offset($pagination->offset)            ->limit($pagination->limit)            ->all();         return $this->render('index', [            'countries' => $countries,            'pagination' => $pagination,        ]);    }

（推荐教程：yii框架）

2、数据库配置文件db.php代码如下：

<?php return [    'class' => 'yii\db\Connection',    'dsn' => 'mysql:host=localhost;dbname=yii2basic',    'username' => 'root',    'password' => '',    'charset' => 'utf8',     // Schema cache options (for production environment)    //'enableSchemaCache' => true,    //'schemaCacheDuration' => 60,    //'schemaCache' => 'cache',];

解决方法：

将PDO连接中的dsn的host由“localhost”改为“127.0.0.1”即可，打开文件DB.PHP，修改如下：

<?php return [    'class' => 'yii\db\Connection',    'dsn' => 'mysql:host=127.0.0.1;dbname=yii2basic',    'username' => 'root',    'password' => '',    'charset' => 'utf8',     // Schema cache options (for production environment)    //'enableSchemaCache' => true,    //'schemaCacheDuration' => 60,    //'schemaCache' => 'cache',];

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