diff --git a/migrations/000.358.sql b/migrations/000.358.sql
new file mode 100644
index 0000000..bf592c3
--- /dev/null
+++ b/migrations/000.358.sql
@@ -0,0 +1,6 @@
+ALTER TABLE discount_codes ADD CONSTRAINT valid_values CHECK (
+	value >= 0
+	and (
+		type != '%' or (type = '%' and value <= 100)
+	)
+);