void UpdateItem(MerchantTableItemEntry entry)
    {
        string query = "UPDATE merchant_item";
        query += " SET ";
        query += entry.UpdateList ();
        query += " WHERE id=?id";

        // Setup the register data
        List<Register> update = new List<Register> ();
        foreach (string field in entry.fields.Keys) {
            update.Add (entry.fieldToRegister (field));
        }

        DatabasePack.Update (DatabasePack.contentDatabasePrefix, query, update);
    }