Comment connecter Yii2 à PostgreSql

$dev = [
    'class'    => 'yii\db\Connection',
    'dsn'      => 'pgsql:host=122.112.182.211;port=8000;dbname=sdk_info',
    'username' => 'dbadmin',
    'password' => 'Styl2018@',
    'charset'  => 'utf8',
//    'emulatePrepare' => true
];
return $dev;

class TestSdkVsent extends Base
{
    public static function getDb()
    {
        return \Yii::$app->dbDws;
    }
    public static function tableName()
    {
        return 'sdk_info.tb_sdk_vsent'; // TODO: Change the autogenerated stub
    }
    public static function test()
    {
        $find = static::find();
        $result = $find->select('rtt')->limit(1) ->asArray()->one();
        return $result;
    }
}

$result = $find->select('rtt')->limit(1)->asArray()->one(); 查询到一条数据返回

$result = $find->select('rtt')->asArray()->one(); 会查询所有的数据返回一条