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Question

I want to create an invoice of every 2 week. An invoice can have 1 or more orders between 1 to 15 and 16 to 31 order_date . What are the way doing that?

Let assume the table design is:

order table
- order_id (PK)
- user_id (FK)
- total
- status
- order_date
- invoice_id (FK, default is 0)

invoice table
- invoice_id (PK)
- invoice_date
- total (total of all orders that is linked to order.invoice_id)
- status (Paid, Unpaid, etc)

//order.invoice_id can have multiple same invoice id

First Solution:

Run via Crob Job every 2 week. It scan through the order table (find order_date between 1 to 15 or 16 to 31 and status = 1) and then add into invoice table and then update the order.invoice_id

If today date is 11th June 2010 then it will insert a row in the invoice table and the invoice_date would be 01 June 2010. PHP will check the invoice_date before adding a row, if it already exist then it will update order.invoice_id instead.

Second Solution:

Change the order.status to 1 manually from the backend then it will do similar functionality as "First Solution" (apart from Cron Job)

Pseudo code:

NowDate = Date();

//Invoice Date can be 01 or 16 date current month
InvoiceDate = InvoiceDate(NowDate)

if (there is invoice for InvoiceDate) {
  invoiceNumber = getNumber(invoice)
} else {
  invoiceNumber = new Invoice(InvoiceDate)
}
new Order(invoiceNumber, orderitems)

Which will be better or do you have other better solution?

Answer 1

I really like cron for scheduling. It does one thing and it does it well.

The other design aspect that is very desirable for scheduled tasks is to be idempotent , which means you can run it again without doing any damage.

In your case, this means your updates/inserts must handle having already been run for the time period. The reason you want this is firstly defensive (in case it's accidentally re-run) and robust (in case you need to re-run it)