diff --git a/sql-schema/094.sql b/sql-schema/094.sql
new file mode 100644
index 000000000..dd0f72667
--- /dev/null
+++ b/sql-schema/094.sql
@@ -0,0 +1,3 @@
+DELETE a1 FROM alerts a1, alerts a2 WHERE a1.id < a2.id AND a1.device_id = a2.device_id AND a1.rule_id = a2.rule_id;
+ALTER TABLE `alerts` ADD UNIQUE `unique_alert`(`device_id`, `rule_id`);
+