Moved logger alias to const

Author: federivo

lib/internal/Magento/Framework/DB/Logger/LoggerProxy.php

@@ -9,10 +9,15 @@
 class LoggerProxy extends LoggerAbstract
 {
     /**
-     * Logger alias
+     * Logger alias param name
      */
     const PARAM_ALIAS = 'db_logger_alias';
 
+    /**
+     * File logger alias
+     */
+    const FILE_LOGGER_ALIAS = 'file';
+
     /**
      * @var LoggerAbstract
      */
@@ -37,7 +42,7 @@ public function __construct(
     )
     {
         switch ($loggerAlias) {
-            case "file":
+            case self::FILE_LOGGER_ALIAS:
                 $this->logger = $loggerFileFactory->create();
                 break;
             default: