diff --git a/database.py b/database.py
index d39a95b..383e566 100644
--- a/database.py
+++ b/database.py
@@ -39,6 +39,7 @@ def add_user(db, *, username, password, email, parent, status):
 
 	# Add the user into the database
 	cursor = db.cursor()
+	cursor.execute('PRAGMA foreign_keys = ON;') # Fail if we insert a user with bogus parent field
 	cursor.execute('INSERT INTO users VALUES (?, ?, ?, ?, ?, ?, ?);', (userid, parent, status, password, username, email, ''))
 
 def initialize_users(db, admin_user, admin_password):
@@ -58,7 +59,9 @@ def initialize_users(db, admin_user, admin_password):
 		username text NOT NULL,
 		email text NOT NULL,
 
-		comment text NOT NULL
+		comment text NOT NULL,
+
+		FOREIGN KEY(parent) REFERENCES users(id)
 	);''')
 
 	add_user(db, username = admin_user, password = admin_password, email = '', parent = None, status = userstatus.admin)