优化结构

backend/config/constants.php

+<?php
+defined('PREFIX') or define('PREFIX', 'ROMENS_NEW_');

backend/config/db.php

+<?php
+return [
+    'components' => [
+        'db' => [
+            'class' => 'yii\db\Connection',
+            'dsn' => 'mysql:host=localhost;dbname=weishopdb',
+            'username' => 'root',
+            'password' => '',
+            'charset' => 'utf8',
+        ],
+        //add db1，2，3，4，5，6
+        'db-100' => [
+            'class' => 'yii\db\Connection',
+            'dsn' => 'mysql:host=localhost;dbname=weishopdbs',
+            'username' => 'root',
+            'password' => '',
+            'charset' => 'utf8',
+        ],
+    ]
+];

backend/config/main.php

@@ -5,7 +5,6 @@ $params = array_merge(
     require __DIR__ . '/params.php',
     require __DIR__ . '/params-local.php'
 );
-
 return [
     'id' => 'app-backend',
     'basePath' => dirname(__DIR__),
@@ -65,22 +64,6 @@ return [
                 'GET swaggers/swagger/<id>'=>'swagger/swagger',
             ],
         ],
-        // default db
-        'db' => [
-            'class' => 'yii\db\Connection',
-            'dsn' => 'mysql:host=localhost;dbname=weishopdb',
-            'username' => 'root',
-            'password' => '',
-            'charset' => 'utf8',
-        ],
-        //add db1，2，3，4，5，6
-        'db-100' => [
-            'class' => 'yii\db\Connection',
-            'dsn' => 'mysql:host=localhost;dbname=weishopdbs',
-            'username' => 'root',
-            'password' => '',
-            'charset' => 'utf8',
-        ],
         'redis' => [
             'class' => 'yii\redis\Connection',
             'hostname' => 'r-m5ed79b6945c5a14.redis.rds.aliyuncs.com',

backend/web/index.php

 <?php
 defined('YII_DEBUG') or define('YII_DEBUG', true);
 defined('YII_ENV') or define('YII_ENV', 'dev');
-defined('PREFIX') or define('PREFIX', 'ROMENS_NEW_');
+
 require __DIR__ . '/../../vendor/autoload.php';
 require __DIR__ . '/../../vendor/yiisoft/yii2/Yii.php';
 require __DIR__ . '/../../common/config/bootstrap.php';
 require __DIR__ . '/../config/bootstrap.php';
-
+require __DIR__ . '/constants.php';
 $config = yii\helpers\ArrayHelper::merge(
     require __DIR__ . '/../../common/config/main.php',
     require __DIR__ . '/../../common/config/main-local.php',
     require __DIR__ . '/../config/main.php',
-    require __DIR__ . '/../config/main-local.php'
+    require __DIR__ . '/../config/main-local.php',
+    require __DIR__ . '/../config/db.php'
 );
 
 (new yii\web\Application($config))->run();