diff --git a/up/collapse_participants.sql b/up/collapse_participants.sql
index f4d86a4bb..691b0018a 100644
--- a/up/collapse_participants.sql
+++ b/up/collapse_participants.sql
@@ -1,4 +1,4 @@
 DROP TABLE music_session_clients;
 
-ALTER TABLE connections ADD COLUMN music_session_id VARCHAR(64) REFERENCES music_sessions(id); 
+ALTER TABLE connections ADD COLUMN music_session_id VARCHAR(64) REFERENCES music_sessions(id) ON DELETE SET NULL; 
 ALTER TABLE connections ADD COLUMN ip_address VARCHAR(64);