Thread: BUG #17247: How to avoid crating multiple Foreign keys on same column on same table.
BUG #17247: How to avoid crating multiple Foreign keys on same column on same table.
From
PG Bug reporting form
Date:
The following bug has been logged on the website: Bug reference: 17247 Logged by: bipsy Nair Email address: nbipin29@gmail.com PostgreSQL version: 13.4 Operating system: Any OS Description: Issue: Postgres engine allows multiple FK on same columns for a same table.This cause duplication and unwanted use of space . If we accidentally run a script multiple times it creates the FK mulitple times. Ran the following statement 3 times : to add a foreign key ALTER TABLE admin.emp ADD FOREIGN KEY (deptno) REFERENCES admin.dept (deptno) ON DELETE NO ACTION; I see 3 its created thrice . In Oracle this statement should fail. Is there any way this restriction can be applied on PG. admin emp_deptno_fkey emp deptno admin dept deptno admin emp_deptno_fkey1 emp deptno admin dept deptno admin emp_deptno_fkey2 emp deptno admin dept deptno Please advice.
Re: BUG #17247: How to avoid crating multiple Foreign keys on same column on same table.
From
Juan José Santamaría Flecha
Date:
On Tue, Oct 26, 2021 at 9:07 AM PG Bug reporting form <noreply@postgresql.org> wrote:
Issue: Postgres engine allows multiple FK on same columns for a same
table.This cause duplication and unwanted use of space . If we accidentally
run a script multiple times it creates the FK mulitple times.
Ran the following statement 3 times : to add a foreign key
ALTER TABLE admin.emp
ADD FOREIGN KEY (deptno)
REFERENCES admin.dept (deptno)
ON DELETE NO ACTION;
I see 3 its created thrice . In Oracle this statement should fail. Is there
any way this restriction can be applied on PG.
admin emp_deptno_fkey emp deptno admin dept deptno
admin emp_deptno_fkey1 emp deptno admin dept deptno
admin emp_deptno_fkey2 emp deptno admin dept deptno
Please advice.
Using a named constraint can prevent this:
ALTER TABLE admin.emp ADD CONSTRAINT emp_deptno_fkey FOREIGN KEY (deptno) REFERENCES admin.dept (deptno) ON DELETE NO ACTION;
Regards,
Juan José Santamaría Flecha