public boolean store(){
        if(this.account_num == -1)
            return false;
        SQLiteJDBC db = new SQLiteJDBC();
        String sql = String.format(
            "INSERT INTO card_accounts(account_num,loyalty_program, user_id,expiry_date,issuer,points_earned)" +
            "VALUES('%d','%d','%d', '%s','%d','%d');",
            this.account_num,
            this.loyalty_program.getID(),
            this.customer.getID(),
            (new SimpleDateFormat("dd-MM-yyyy")).format(this.expiry_date), 
            this.issuer.getID(),
            this.points_earned
        );
        if(db.updateQuery(sql)>0){
            db.close();
            return true;
        }
        else{
            db.close();
            return false;
        } 
    }