diff --git a/src/Entity/JobOrder.php b/src/Entity/JobOrder.php
index 053c98e9..ddfbd204 100644
--- a/src/Entity/JobOrder.php
+++ b/src/Entity/JobOrder.php
@@ -179,6 +179,13 @@ class JobOrder
      */
     protected $tickets;
 
+    // reference job order
+    /**
+     * @ORM\OneToOne(targetEntity="JobOrder")
+     * @ORM\JoinColumn(name="ref_jo_id", referencedColumnName="id")
+     */
+    protected $ref_jo;
+
     public function __construct()
     {
         $this->date_create = new DateTime();
@@ -446,4 +453,15 @@ class JobOrder
     {
         return $this->tickets;
     }
+
+    public function setReferenceJO(JobOrder $ref_jo)
+    {
+        $this->ref_jo = $ref_jo;
+        return $this;
+    }
+
+    public function getReferenceJO()
+    {
+        return $this->ref_jo;
+    }
 }