diff --git a/trytond/ir/export.py b/trytond/ir/export.py
index 9210f39243..8ac941531b 100644
--- a/trytond/ir/export.py
+++ b/trytond/ir/export.py
@@ -21,5 +21,5 @@ class ExportLine(ModelSQL, ModelView):
     "Export line"
     __name__ = 'ir.export.line'
     name = fields.Char('Name')
-    export = fields.Many2One('ir.export', 'Export',
-       select=True)
+    export = fields.Many2One('ir.export', 'Export', select=True, required=True,
+        ondelete='CASCADE')