How to prevent inserts in the parent table?

Question

There is a table t which has inherited children. I want that only the children can receive inserts. What is the best way to force that the parent table rejects inserts?

create table t (c int);
create table t1 () inherits (t);

This should not be possible:

insert into t (c) values (1);

EDIT:

I found a model visible solution in addition to the one from @wildplasser:

create table tfk (c integer unique check(false));
create table t (c integer, foreign key (c) references tfk(c));

Now it is not possible to insert into t UNLESS it is a null value, and still possible to insert into its children. It can be a good solution if that columnn is already constrained as not null but not enough otherwise. Or does someone know a trick to make the above work for null values?

News:

I asked for a new syntax in the postgresql list and it was done for 9.2:

Allow CHECK constraints to be declared NO INHERIT (Nikhil Sontakke, Alex Hunsaker)

This makes them enforceable only on the parent table, not on child tables.

Answer 1

You could use a before insert trigger to raise an error or redirect to the correct table.