ERD structure, looping? Yay or Nay?

[Ethan_U]

Hey guys I’m doing a pretty straightforward Inventory app that generates PURCHASE ORDERS and LINE ITEMS based on STOCK ITEMS from Vendors.

If I include a ref column in the LINE ITEMS to both the original STOCK ITEM and PURCHASE ORDER does this loop create issues? It seemed odd to me to have the line item only refer to the PURCHASE ORDER and only be able to access the STOCK ITEM columns with a Select expression rather than a deref.

I found an ERD article from Oracle that actually has the exact same structure which makes sense to me but I have heard occasionally that loops are a no no. My database knowledge is minimal so I thought someone might chime in on whether Appsheet will be angry with me or nice. Article link here: (Developing an Application)

I’d love some feedback on this. Thank you guys for any help.