Nullable true in timeDiscovery but default is 0.

src/FTTHBundle/Entity/OLT.php

@@ -186,7 +186,7 @@ class OLT implements DeviceInterface, TenancyIdTraitInterface, LocationInterface
     protected $backups;
 
     /**
-     * @ORM\Column(type="integer", options={"unsigned":true, "default":0})
+     * @ORM\Column(type="integer", nullable=true, options={"unsigned":true, "default":0})
      */
     protected $timeDiscovery = 0;