Given tables A, B and C, where C holds a foreign key to both A and B (i.e. C is a "join table"), is it possible to define a constraint so that C contains the whole Cartesian product A x B without using triggers in MariaDB 10.2?
(In other words, for every a in A and every b in B is is possible to enforce the existence of one c in C such that c has a foreign key to a and b)
If not, is there a way to redesign the three tables so that the constraint is enforceable, while keeping 4NF?
