Question

An invoice can contain 1 or more orders, how to archive this?

Example of Invoice:

OrderID |      Order Date    |   Amount
   31            10/02/2011         £1.50
   43            12/02/2011         £1.50
   74            13/02/2011         £5.00
                                   =======
                            Total   £8.00 

If the Total is minus (eg: -8.00), it mean client owes me money.
Without minus, I pay client some money.

Here what I came up with:

Orders Table

CREATE TABLE IF NOT EXISTS `orders` (
  `OrderID` int(11) NOT NULL AUTO_INCREMENT,
  `Total` decimal(6,2) NOT NULL,
  `OrderDate` datetime NOT NULL,
  `Status` int(11) NOT NULL,
  `userID` int(11) NOT NULL,
  `InvoiceID` int(11) NOT NULL,
  PRIMARY KEY (`OrderID`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

Invoice Table

CREATE TABLE IF NOT EXISTS `invoice` (
  `InvoiceID` int(11) NOT NULL DEFAULT '0',
  `InvoiceDate` datetime NOT NULL,
  `Amount` decimal(6,2) NOT NULL,
  `Status` int(11) NOT NULL,
  PRIMARY KEY (`InvoiceID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

invoice.Status (0 Processing, 1 Invoice Sent, 2 Cancelled, 3 Completed)
or what better status can be?

Payment Table

CREATE TABLE IF NOT EXISTS `payment` (
  `PaymentID` int(11) NOT NULL AUTO_INCREMENT,
  `InvoiceID` int(11) NOT NULL,
  `Amount` decimal(6,2) NOT NULL,
  `DatePayment` datetime NOT NULL,
  `PaymentType` int(11) NOT NULL,
  PRIMARY KEY (`PaymentID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

payment.PaymentType = (1: Payment Received From Customer (Owes Money), 2: Payment Sent To Customer)

Database Result:

mysql> select * from orders;
+---------+-------+---------------------+--------+--------+-----------+
| OrderID | Total | OrderDate           | Status | userID | InvoiceID |
+---------+-------+---------------------+--------+--------+-----------+
|       1 | 20.00 | 2011-06-18 15:51:51 |      1 |    123 |         1 |
|       2 | 10.00 | 2011-06-19 15:51:57 |      1 |    123 |         1 |
|       3 |  5.00 | 2011-06-20 15:52:00 |      1 |    123 |         1 |
+---------+-------+---------------------+--------+--------+-----------+

mysql> select * from invoice;
+-----------+---------------------+--------+--------+
| InvoiceID | InvoiceDate         | Amount | Status |
+-----------+---------------------+--------+--------+
|         1 | 2011-06-30 15:55:21 |  35.00 |      1 |
+-----------+---------------------+--------+--------+

mysql> select * from payment;
+-----------+-----------+--------+---------------------+-------------+
| PaymentID | InvoiceID | Amount | DatePayment         | PaymentType |
+-----------+-----------+--------+---------------------+-------------+
|         1 |         1 |  35.00 | 2011-06-29 15:56:16 |           1 |
+-----------+-----------+--------+---------------------+-------------+

Im I on the right path? What can be improved/changed or suggestion?

Thanks.

Answer 1

Looks good.

The only thing I would add are some details like transaction id / check number to the payment table. This way you keep all the payment details together.