We use an in-house MRP system for our production of cosmetics. I wrote the system some five years ago.
Since the beginning I always wondered how systems like SAP or other MRP ERP solutions handle this question.
The question is: Every product you have in your database has a count, lets call it "number_in_stock". It is everything you ever bought of this item minus everything you ever sold plus everything you ever produced minus everything you used in the production process.
Our 5 year old system handles this very well.
However the other day I deleted some 5 year old invoices of purchases which had some obsolete data on them.... and... obviously out "number_in_stock" figure showed negative.. because the purchase orders five years old got deleted.
I thought I should come up with a way to make this system more secure.
We check our inventory each month and correct the numbers, sometimes something gets typed wrongly, something gets lost/stolen/missing or whatever..hehe.
Would there be an elegant way to make this inventory dates be new " set points" for the system, so that older events, purchase orders, sales orders, production orders or productions order items would NOT counted anymore.
How do they do in SAP, which is designed for BIIIG companies.
Any ideas? Was I even clear :-)