diff --git a/src/FieldTypes/Configs/Attributes/DbType.php b/src/FieldTypes/Configs/Attributes/DbType.php
index 1c834c4..469c68e 100644
--- a/src/FieldTypes/Configs/Attributes/DbType.php
+++ b/src/FieldTypes/Configs/Attributes/DbType.php
@@ -3,6 +3,7 @@
 namespace SolutionForest\FilamentFieldGroup\FieldTypes\Configs\Attributes;
 
 use Attribute;
+
 /**
  * @property string $drive The drive of the database.
  * @property string $type The type of the field in database.
diff --git a/src/FieldTypes/Configs/Contracts/FieldTypeConfig.php b/src/FieldTypes/Configs/Contracts/FieldTypeConfig.php
index 4573b05..15602fa 100644
--- a/src/FieldTypes/Configs/Contracts/FieldTypeConfig.php
+++ b/src/FieldTypes/Configs/Contracts/FieldTypeConfig.php
@@ -35,5 +35,5 @@ public static function getConfigNames(): array;
      *
      * @return array<string,mixed> | array<string,array<string,mixed>>
      */
-    public static function getDbTypeMapping(string $drive = null): array;
+    public static function getDbTypeMapping(?string $drive = null): array;
 }
diff --git a/src/FieldTypes/Configs/FieldTypeBaseConfig.php b/src/FieldTypes/Configs/FieldTypeBaseConfig.php
index 14f4a5f..05b89f0 100644
--- a/src/FieldTypes/Configs/FieldTypeBaseConfig.php
+++ b/src/FieldTypes/Configs/FieldTypeBaseConfig.php
@@ -102,7 +102,7 @@ public static function getConfigNames(): array
     }
 
     /** {@inheritDoc} */
-    public static function getDbTypeMapping(string $drive = null): array
+    public static function getDbTypeMapping(?string $drive = null): array
     {
         $attributes = static::findFieldConfigAttribute(static::class, DbType::class);