diff --git a/src/Libs/ModelMySQL.php b/src/Libs/ModelMySQL.php
index 4f1f8d7..3b50f3e 100644
--- a/src/Libs/ModelMySQL.php
+++ b/src/Libs/ModelMySQL.php
@@ -223,8 +223,10 @@ class ModelMySQL {
     $atts = $this->getVars();
     
     foreach ($atts as $key => $value) {
-      $value = static::db()->real_escape_string($value);
-      $set[]="$key='$value'";
+      if (isset($value)) {
+        $value = static::db()->real_escape_string($value);
+        $set[]="$key='$value'";
+      }
     }
     
     $table = static::table();