# Is it OK to have an entity in an ER diagram without a relationship

database-designerd

I'm creating an ER diagram for a class assignment and I was wondering if it would be possible to create an entity that had no direct relationship to any other entity, and simply use foreign keys to connect them. The diagram below illustrates what I'd like to do

Basically, my diagram is starting to get really complex and it would be great if I didn't have to maintain a connection between every single entity.

FWIW, I'm using Chen and Crow's Foot notation, if that's any help.

So to answer your question by another route: You can display as many or as few diagrams on your ER diagram as are required to show the information you're trying to represent. But if you choose to omit a relationship for purposes of clarity, it would still make sense to make a note that the R is omitted. I would personally but a -{#} with a number inside the related circles for each entity, with a footnote for that # at the bottom of the page. That way other readers won't have to ask if there should be another relation.