Parent and Child table question Another question on the photo organisation and storage app design I am working on for my class: the specifications mention that people are able to be recorded in the database even if they don't appear in any photograph and that a location can be recorded even if there aren't any photographs associated with them. I'm not sure I understand what this would mean. Would you say this would mean the person and location tables should be parent tables to the photo table or am I missing something?
Basically it comes to this:

Your photo is abourt a house, that belongs to a person. your photo has no persons in iit, but it still belongs to the person, so you can add a relationship to the photo.

The same goes for for locations the Washington Monument  is located between  Capitol and Lincoln Memorial so you can add a relationship between tose .