How to update records

[Glad2000]

I’m building an application. Let’s say, we have 3 o more buildings, each building has 4 o mores floors, each floor has 7 o more apartments.
Each apartment needs or wood doors or metal doors, Kemmore refrigerator or GE refrigerator, in other words there are many options for each product.

Let’s take one building. You review each floor and each apartment. When finished the review you have a big list of products. You get that with a DSum for that particular building.
Now you need to make several Purchase Orders. Let’s say we need 100 GE refrigerators but at this time we are going to buy only 30, in a week other 20, etc. But after the first order you decide to change to 80 GE refrigerators not 100.
How can you keep updated the big Purchase Order and the small POs.?
Thanks.

 

[BNPMike]

One way is to to retain full granularity.

If you have a purchase order field against each item then you will see which actual items were ordered in the batch of 30. You don't suddenly wake up in the morning and decide to order 20 less refrigerators. Presumably you are delaying 20 or you have changed 20 to another product. Either way if you ar managing the numbers by managing individual items you will always have an audit trail and keep track of bought versus outstanding.

Once you start dealing with aggregates you lose the ability to work out where they came from and are guaranteed to end up with 2 unclaimed refrigerators at the end of the project.