diff --git a/Models/EmployeeHistoryMapper.php b/Models/EmployeeHistoryMapper.php
index 4a59b5e..c3a4cfb 100644
--- a/Models/EmployeeHistoryMapper.php
+++ b/Models/EmployeeHistoryMapper.php
@@ -18,4 +18,11 @@ use phpOMS\DataStorage\Database\DataMapperAbstract;
 
 final class EmployeeHistoryMapper extends DataMapperAbstract
 {
+    /**
+     * Primary field name.
+     *
+     * @var string
+     * @since 1.0.0
+     */
+    protected static $primaryField = 'hr_staff_history_id';
 }