Feature Request: foreign key integrity

[ghost]

Postgresql does not allow for foreign key constraints from a base table to some other table. See Caveats section in https://www.postgresql.org/docs/9.5/static/ddl-inherit.html

Scenario:

• You have a parent table called persons with a primary key id. You have students and teachers tables that inherit from persons.

• You have another table called orders and it has an attribute person_id.

• You'd like to add a foreign_key constraint from persons.id to orders.id. Such that anytime you inserted a student or teacher record it would maintain this constraint. However postgresql will not allow this as the record must exist in the base class.

Request:

• Optionally allow a way to maintain this foreign_key constaint at the application layer (MTI)

• For instance, if you tried to insert an orders record and the person did exist in the persons table then MTI would throw a foreign constraint exception.