--- a/Resources/Orthanc/Core/Enumerations.cpp	Fri Feb 02 18:11:32 2018 +0100
+++ b/Resources/Orthanc/Core/Enumerations.cpp	Thu Mar 22 17:32:05 2018 +0100
@@ -161,6 +161,9 @@
       case ErrorCode_NullPointer:
         return "Cannot handle a NULL pointer";
 
+      case ErrorCode_DatabaseUnavailable:
+        return "The database is currently not available (probably a transient situation)";
+
       case ErrorCode_SQLiteNotOpened:
         return "SQLite: The database is not opened";
 
@@ -1617,6 +1620,9 @@
       case ErrorCode_NotAcceptable:
         return HttpStatus_406_NotAcceptable;
 
+      case ErrorCode_DatabaseUnavailable:
+        return HttpStatus_503_ServiceUnavailable;
+
       default:
         return HttpStatus_500_InternalServerError;
     }