diff --git a/library/think/Error.php b/library/think/Error.php
index 7a5fb4db..9fdd240a 100644
--- a/library/think/Error.php
+++ b/library/think/Error.php
@@ -11,7 +11,9 @@
 
 namespace think;
 
+use think\Config;
 use think\exception\ErrorException;
+use think\Log;
 
 class Error
 {
diff --git a/library/think/Model.php b/library/think/Model.php
index 53ad11f6..d387296e 100644
--- a/library/think/Model.php
+++ b/library/think/Model.php
@@ -23,7 +23,7 @@ abstract class Model implements \JsonSerializable, \ArrayAccess
     // 数据库对象池
     private static $links = [];
     // 数据库配置
-    protected static $connection;
+    protected static $connection = [];
     // 数据表名称
     protected static $table;
     // 回调事件
diff --git a/library/think/db/Connection.php b/library/think/db/Connection.php
index a2887745..aa4ce76d 100644
--- a/library/think/db/Connection.php
+++ b/library/think/db/Connection.php
@@ -98,7 +98,7 @@ abstract class Connection
      * @access public
      * @param array $config 数据库配置数组
      */
-    public function __construct($config = '')
+    public function __construct(array $config = [])
     {
         if (!empty($config)) {
             $this->config = array_merge($this->config, $config);
@@ -170,12 +170,12 @@ abstract class Connection
     /**
      * 连接数据库方法
      * @access public
-     * @param mixed $config 连接参数
+     * @param array $config 连接参数
      * @param integer $linkNum 连接序号
      * @param false|array $autoConnection 是否自动连接主数据库（用于分布式）
      * @return \PDO
      */
-    public function connect($config = '', $linkNum = 0, $autoConnection = false)
+    public function connect(array $config = [], $linkNum = 0, $autoConnection = false)
     {
         if (!isset($this->links[$linkNum])) {
             if (!empty($config)) {