diff --git a/src/Entity/DoctrineStorageRatio.php b/src/Entity/DoctrineStorageRatio.php
index afa02752..86c37bfa 100644
--- a/src/Entity/DoctrineStorageRatio.php
+++ b/src/Entity/DoctrineStorageRatio.php
@@ -4,18 +4,17 @@
 
 namespace Tbbc\MoneyBundle\Entity;
 
-/**
- * Class DoctrineStorageRatio.
- */
 class DoctrineStorageRatio
 {
-    private mixed $id = null;
+    private ?int $id = null;
 
-    public function __construct(private ?string $currencyCode = null, private ?float $ratio = null)
-    {
+    public function __construct(
+        private ?string $currencyCode = null,
+        private ?float $ratio = null,
+    ) {
     }
 
-    public function getId(): mixed
+    public function getId(): int
     {
         return $this->id;
     }
diff --git a/src/Entity/RatioHistory.php b/src/Entity/RatioHistory.php
index e797a412..d966815c 100644
--- a/src/Entity/RatioHistory.php
+++ b/src/Entity/RatioHistory.php
@@ -7,12 +7,9 @@
 use DateTime;
 use DateTimeInterface;
 
-/**
- * Class RatioHistory.
- */
 class RatioHistory
 {
-    protected mixed $id = null;
+    protected ?int $id = null;
     protected string $referenceCurrencyCode = '';
     protected string $currencyCode = '';
     protected float $ratio = 0;
@@ -23,14 +20,14 @@ public function __construct()
         $this->savedAt = new DateTime();
     }
 
-    public function setId(mixed $id): self
+    public function setId(int $id): self
     {
         $this->id = $id;
 
         return $this;
     }
 
-    public function getId(): mixed
+    public function getId(): int
     {
         return $this->id;
     }