diff --git a/roomserver/storage/postgres/membership_table.go b/roomserver/storage/postgres/membership_table.go
index 3cfc09fd0..875539bdf 100644
--- a/roomserver/storage/postgres/membership_table.go
+++ b/roomserver/storage/postgres/membership_table.go
@@ -61,7 +61,7 @@ CREATE TABLE IF NOT EXISTS roomserver_membership (
 	-- room joins.
 	target_local BOOLEAN NOT NULL DEFAULT false,
 	forgotten BOOLEAN NOT NULL DEFAULT FALSE,
-	displayname TEXT,
+	displayname TEXT NOT NULL DEFAULT "",
 	UNIQUE (room_nid, target_nid)
 );
 `
diff --git a/roomserver/storage/sqlite3/membership_table.go b/roomserver/storage/sqlite3/membership_table.go
index c87f7c5e8..810e9a18c 100644
--- a/roomserver/storage/sqlite3/membership_table.go
+++ b/roomserver/storage/sqlite3/membership_table.go
@@ -37,7 +37,7 @@ const membershipSchema = `
 		event_nid INTEGER NOT NULL DEFAULT 0,
 		target_local BOOLEAN NOT NULL DEFAULT false,
 		forgotten BOOLEAN NOT NULL DEFAULT false,
-		displayname TEXT,
+		displayname TEXT NOT NULL DEFAULT "",
 		UNIQUE (room_nid, target_nid)
 	);
 `