diff --git a/src/PaymentServer/Persistence.hs b/src/PaymentServer/Persistence.hs
index f5cf5fc1ab5be4fc00d266f0c897e651c970a4f2..d4451dca01065658295715623f34e76cd8ba912f 100644
--- a/src/PaymentServer/Persistence.hs
+++ b/src/PaymentServer/Persistence.hs
@@ -153,6 +153,7 @@ insertVoucherAndFingerprint dbConn voucher fingerprint =
 getDBConnection :: Text -> IO VoucherDatabaseState
 getDBConnection name = do
   dbConn <- Sqlite.open (unpack name)
+  Sqlite.execute_ dbConn "PRAGMA foreign_keys = ON"
   Sqlite.execute_ dbConn "CREATE TABLE IF NOT EXISTS vouchers (id INTEGER PRIMARY KEY, name TEXT UNIQUE)"
   Sqlite.execute_ dbConn "CREATE TABLE IF NOT EXISTS redeemed (id INTEGER PRIMARY KEY, voucher_id INTEGER, fingerprint TEXT, FOREIGN KEY (voucher_id) REFERENCES vouchers(id))"
   return $ SQLiteDB dbConn