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.
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
personswith a primary keyid. You havestudentsandteacherstables that inherit frompersons.You have another table called
ordersand it has an attributeperson_id.You'd like to add a foreign_key constraint from
persons.idtoorders.id. Such that anytime you inserted astudentorteacherrecord 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
ordersrecord and the person did exist in thepersonstable then MTI would throw a foreign constraint exception.