In the FileMaker relationship graph and the relationship definition window, does it matter which table is on the left or right side?

Question 1

Strictly speaking, the answer here is that there is no difference between the two lines.

In FileMaker, though, connections are between Table Occurrences rather than between the tables themselves. The link between these Table Occurrences determines things like the sort order and whether a new record can be added directly to a related Table.

So, for instance:

TableOccurrenceA1::Site_id = TableOccurrenceB1::Site_id

and

TableOccurrenceA2::Site_id = TableOccurrenceB1::Site_id

Both link Table A to Table B, through Occurrences A1 = B1 and A2 = B1.

But the way these occurrences are set up can be different, even if the relationship is the same. So let us say that the relationship TableOccurrenceA1 = TableOccurrenceB1 is sorted by transaction date in the descending order, most recent dates first.

Let's also say that the relationship TableOccurrenceA2 = TableOccurrenceB1 is sorted by billing amount in the descending order, highest billed amounts first.

On a layout displaying TableOccurrenceB1, I could use the different Table Occurrences to display two different data points. For example, I could show the Most Recent Transaction by displaying field:

TableOccurrenceA1::transaction date

I could show the Largest Transaction by displaying the field:

TableOccurrenceA2::billing amount

Note that we're using the sort order set in the relationship diagram to automatically pull only the one value that we want, based on two different Table Occurrences of TableA with the same relationship.

Question 2

In Filemaker the relationship are same as we see and as it sounds.

But the difference would be more clearly viewed while designing a layout.

That's where the two relationships have different role.

Whether we are having the layout in the Filemaker based on Table A as the parent table layout or Table B.