How to do an exclusive specialization in sql?

0

Well, I have finished the relationship entity diagram of the database I am creating, and there is a service entity in it, which has two exclusive specializations (one or the other, can not be both), monthly and simple.

In the implementation generated 3 tables, monthly and simple has the service identifier as the foreign key, but how can I prevent it from being able to implement the same instance in these two tables and enforce this exclusive?

    
asked by anonymous 15.02.2018 / 03:50

0 answers