Multiple rows inside a column#449

For example i have a client that wants to purchase more items from me and i need to record those items as well as the phone number date supplier etc. I cannot insert multiple lines inside a cell.
ID Name Part no. Parts Supplier
1 Andreas TCM12 starter Sup1
VMR443 tire Sup1
JJ192 door Sup2
2 John VMR443 tire Sup1
3 Alex JJ192 door Sup2
4 Ana 2331F handle Sup3
2332F handle Sup3

Or a condition where it allows to add another child to the parent row.

Some method to conveniently resolve this problem is very high on my wishlist too.
I believe quite many people would benefit from this, it’s basically the child record functionality in suggestion #83 where the multiple items would be the child records of the order record.

I think in the ideal solution, when filling in the order details, the customer would be selected from a foreign key table (where also other customer info would be stored).
Same goes for the items, but it would be possible to select several of them.
However, there’s apparently a technical limitation preventing the use of multi-select box here, and that’s where things get difficult.
If the product list was short, but that might be a rare case, I believe a predefined list of products could be used, then also the multi-select box would be possible.

Another very interesting approach could be, yes, somehow adding more items on-the-fly only when that’s needed, I mean the default behaviour would be just one item in the order.
I’m thinking a button like “Add more items”, which would somehow dynamically present the user a new blank item field, to add item 2 and then clicking the button again for item 3 and so on.
If a max quantity of items in order could be predetermined/limited, these extra fields could actually be already in the database, waiting for use. I’m not sure if there would be a performance impact though, having extra columns for say 10 items per order, if majority of the orders would have only 1 or 2 items.
I was just considering ways to overcome the technical limitations… because going for the extra columns route, I think it would just be a matter of popping up the fields in the user interface when a user needs them.

By the way, just having multiple lines inside a cell actually is already possible, currently at least when separating the lines with the p html tag, but that would not be very convenient especially in daily use.