On Fri, 2006-10-06 at 23:09 +0200, Ivan Sergio Borgonovo wrote: > Is there any good documentation, example, tutorial, pamphlet, discussion... to exploit pg features to obtain "polymorphic" behavior without renouncing to referential integrity? > > Inheritance seems *just* promising. > > Any methodical a approach to the problem in pg context? > I'm not sure if this answers your question, but here's how I do inheritance in the relational model. Just make a "parent" table that holds a more generic object like: CREATE TABLE person (name TEXT PRIMARY KEY, age INT, height NUMERIC); Then a "child" table like: CREATE TABLE student (name TEXT REFERENCES person(name), gpa NUMERIC); Every person, student or otherwise has a record in "person". If, and only if, they are a student they have a record in the "student" table. To select all people, select only from the "person" table. To select all students, select from the join of the two tables. Regards, Jeff Davis
