Schools have techniques used in organizing their departments. Some schools go School -> Term -> Department. Others have stages in between, using the longest being School -> Sub_Campus -> Program -> Term -> Division -> Department.

School, Term, and Department would be the only ones have a tendency to appear in a school's "tree" of departments. An order of those groups never changes, using the second example I gave you being a long. Everything lower is really a 1:N relationship.

Now, I am unsure how to setup the associations between your tables. For instance, what posts have been in Term? Its parent might be a Program, Sub_Campus, or School. Which it's is dependent around the school's system. I possibly could conceive of establishing the Term table to possess foreign secrets its individuals (which all would default to NULL), but I am unsure this is actually the canonical method of doing things here.

Here's one design possibility:

This method uses your personal constraints. Essentially you generalize all hierarchies as those of a long form by presenting generic nodes. If school does not have "sub campus" then just assign it a normal sub campus known as "Primary". For instance, School -> Term -> Department could be considered just like School -> Sub_Campus = Main -> Program=Main -> Term -> Division=Main -> Department. Within this situation, we assign a node known as "Primary" as default when school does not obtain that nodes. You can now simply have a boolean flag property of these generic nodes that signifies that they're just placeholders which flag would permit you to filter it in middle layer or perhaps in UX as needed.

This design will help you to make the most of all relational constraints as always and simplify handling of missing node types inside your code.

It is best to better make use of a general table, known as e.g. Entity which may contain id area along with a self-referencing parent area.

Each relevant table would have a area pointing to Entity's id (1:1). In ways each table will be a child from the Entity table.