mnesia developments

[erlang@REDACTED]

In my further researches into the user manual I _think_ I have
developed a clearer understanding of what the source of my confusion was.

Correct me if I am wrong, please:

the _.hrl file can be used to express a schema which will be loaded when
mnesia is started

or

mnesia's schema can be created on the fly with shell commands (or some
suitable function which encapsulates a set of them).

What I'm not clear on is if there is some sneaky lack of equivalence
between the two methods which isn't made entirely clear in the manual.