multi-shop orders table and sequential order numbers based on shop

Question

I am looking at building a shop solution that needs to be scalable. Currently it retrieves 1-2000 orders on average per day across multiple country based shops (e.g. uk, us, de, dk, es etc.) but this order could be 10x this amount in two years.

I am looking at either using separate country-shop databases to store the orders tables, or looking to combine all into one order table.

If all orders exist in one table with a global ID (auto num) and country ID (e.g uk,de,dk etc.), each countries orders would also need to have sequential ordering. So in essence, we'd have to have a global ID and a country order ID, with the country order ID being sequential for countries only, e.g.

global ID = 1000, country = UK, country order ID = 1000
global ID = 1001, country = DE, country order ID = 1000
global ID = 1002, country = DE, country order ID = 1001
global ID = 1003, country = DE, country order ID = 1002
global ID = 1004, country = UK, country order ID = 1001

THe global ID would be DB generated and not something I would need to worry about. But I am thinking that I'd have to do a query to get the current country order based ID+1 to find the next sequential number. Two things concern me about this: 1) query times when the table has potentially millions of rows of data and I'm doing a read before a write, 2) the potential for ID number clashes due to simultaneous writes/reads.

With a MyISAM table the entire table could be locked whilst the last country order + 1 is retrieved, to prevent ID number clashes.

I am wondering if anyone knows of a more elegant solution?

Cheers, imanc

Answer 1

There is a way of doing this.

INSERT INTO test123 (`Country`, `Country order code`)
SELECT 'UK', MAX(`Country order code`) + 1
FROM test123
WHERE `Country` = 'UK'

This puts a new order for the UK in, it selects the highest order code an adds one. This has been tested, and all that needs to be changed is the names of the tables and fields