diff --git a/src/Adapter/MySQL.php b/src/Adapter/MySQL.php
index 6b9c525..4e20906 100644
--- a/src/Adapter/MySQL.php
+++ b/src/Adapter/MySQL.php
@@ -79,7 +79,7 @@ class MySQL implements AdapterInterface, MigrateInterface, SqlAdapterInterface {
             $pdo->setAttribute(\PDO::ATTR_EMULATE_PREPARES, false);
             $pdo->setAttribute(\PDO::ATTR_AUTOCOMMIT, false);
             $pdo->setAttribute(\PDO::ATTR_DEFAULT_FETCH_MODE, \PDO::FETCH_ASSOC);
-            $pdo->setAttribute(\PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
+            $pdo->setAttribute(\Pdo\Mysql::ATTR_USE_BUFFERED_QUERY, false);
         }
         catch(\PDOException $ex){
             throw $ex;
diff --git a/src/EntityCollection.php b/src/EntityCollection.php
index 7e67902..696d722 100644
--- a/src/EntityCollection.php
+++ b/src/EntityCollection.php
@@ -322,7 +322,7 @@ class EntityCollection extends \ArrayObject implements \JsonSerializable {
                 case is_string($value):
                     $value = (string) $value;
 
-                    $list[$key] = $item->$value;
+                    $list[(string) $key] = $item->$value;
                     break;
             }
         }
diff --git a/src/Repository/JoinBuilderTrait.php b/src/Repository/JoinBuilderTrait.php
index b7ff4d6..114f655 100644
--- a/src/Repository/JoinBuilderTrait.php
+++ b/src/Repository/JoinBuilderTrait.php
@@ -30,7 +30,7 @@ trait JoinBuilderTrait
 
         $fields = (array) $fields;
 
-        usort($fields, fn($e1, $e2) => str_contains($e1, '.') <=> str_contains($e2, '.'));
+        usort($fields, fn($e1, $e2) => str_contains((string) $e1, '.') <=> str_contains((string) $e2, '.'));
 
         # @TODO Apply fff annotation to this too !
         foreach(array_filter($fields, fn($e) => $e && ! isset($this->joined[$e]) ) as $item) {
@@ -127,7 +127,7 @@ trait JoinBuilderTrait
         return $this;
     }
 
-    protected function joinFieldObject(mixed $field, string $entityClass, string $alias = null) : \Stringable
+    protected function joinFieldObject(mixed $field, string $entityClass, ?string $alias = null) : \Stringable
     {
         if ( ! is_object($field) ) {
             return $entityClass::field($field, $alias);
@@ -138,7 +138,7 @@ trait JoinBuilderTrait
     }
 
 
-    protected function joinFieldValue(mixed $value, string $alias = null) : mixed
+    protected function joinFieldValue(mixed $value, ?string $alias = null) : mixed
     {
         if ( $value instanceof EntityField ) {
             $value = clone $value;
@@ -150,4 +150,4 @@ trait JoinBuilderTrait
 
         return $value;
     }
-}
\ No newline at end of file
+}