IRE Indentification: Related Entries

[maciep]

I've read a lot about Related Entries - there are multiple forum posts, articles, videos, etc. But I'm still missing something. How are they actually used?

The docs say, "Related entries let you create or update records on other tables".  They "let" us. Ok, what does that mean. Does the IRE actually do it for us? Or does just "let" us?

And generally, I get "updating" other records. But "creating" them? I don't understand how the IRE would know when to create a Related CI.

For example, let's say a payload for a Windows Server hits the IRE and it identifies an existing CI. It will update  that CI accordingly. Will it also iterate through the Related Entries and then update the related CIs that match. Like if there are 5 Software Installation records currently for that identified CI, does the IRE update those as well?

And what if that payload is for a new CI. Surely it doesn't "create" a record in the Software Installation table, right? I mean, we have classes inheriting Related Entries from Hardware and it would never make sense. Like an IP Switch being related to an MSSql Component or whatever.

So does the IRE actually take action on those related items? And if so, which actions and in which scenarios? Or is it literally just a reference to be used by some other processes to identify records that might need updated?

Does anyone know it well enough to walk me through some sample payloads to explain how the IRE interacts with the Related Entries? 

I think I've read all of the posts/articles that typically get linked in these questions, but I'm just too dumb to get it so far.