Nesting Tables in SQL Server Express

Question

I am creating a purchase order system where someone can store details of their purchase. So I created a database, with tables for supplier information from which we will buy stuff and another table where we store what we are buying.

In the PurchaseOrder table, there are columns for :

• PurchaseOrderNo (Primary)
• BuyerInitials
• DateOfPurchase
• ProjectCode
• Items (linking to the PurchaseItems table)

I want to add another column with Items' details, so I created another table PurchaseItems which has the following columns:

• PurchaseOrderNo. (this would be repeat for each part)
• PartNo
• Description
• Quantity
• UnitAmount
• VATAmount
• TotalAmount

Logically it seems simple, but I can't seem to get my head around on how I would link the tables. Thank you very much for the help :)

Answer 1

Create a seperate table say OrderedItems which maps the PartNo and PurchaseOrderNo. This avoids the repetition of PurchaseOrderNo in each row and also maintains the relation between PurchaseOrder and PurchaseItems table.