diff --git a/deployment/hasura/migrations/Aerie/11_external_events/up.sql b/deployment/hasura/migrations/Aerie/11_external_events/up.sql
index ada6ed3abb..f2c624a58f 100644
--- a/deployment/hasura/migrations/Aerie/11_external_events/up.sql
+++ b/deployment/hasura/migrations/Aerie/11_external_events/up.sql
@@ -147,6 +147,7 @@ create table ui.seen_sources
     constraint seen_sources_references_user
       foreign key (username)
       references permissions.users (username) match simple
+      on delete cascade
 );
 
 comment on table ui.seen_sources is e''