Something that "links" must be unique in the one table(called a Primary key) to the other table (called the Foreign key). We like to use numbers or UUID (unique) so that in the event the other field is NOT unique, there is no confusion in the relationship.
If you artwork has unique name then it can be used for a relationship. If your show has a unique name (probably a location and date), then it can be used for a relationship.
Thanks Beverly. That makes sense. Just to make sure I understand - if I have a uniquely named piece (e.g., Turtle #2) and it is available in 50 editions/prints would I be able to link each edition to a unique show. For example, I might sell Edition #1 at show ABC in 2016 but sell Edition #2 at show XYZ in 2017.
the good news:
what you want to achieve is possible with filemaker.
the bad news:
modelling the data is indeed a challenge. I always ask my customers "what is your atom" ?
In your case the atom is a single piece of work, belonging to an edition, exposed to a specific exhibit, belonging to a named family (turtle #2) and so on, but it must have a unique ID in order to track it down to its details, like to whom it was sold, when, for how much, etc.