Обсуждение: Correct Syntax for alter table ..add constraint

Hi All,
What is the correct syntax for adding a foreign key constraint from the
command line.
I am using v7.1 beta3..... I  am doing the follwoing:                           alter table users
   add constraint age_fk foreign key(age)
 
references age_list(id);
And I get the following error:
flipr=# alter table users
flipr-# add constraint age_fk foreign key(age) references age_list(id);
NOTICE:  ALTER TABLE ... ADD CONSTRAINT will create implicit trigger(s)
for FOREIGN KEY check(s)
ERROR:  <unnamed> referential integrity violation - key referenced from
users not found in age_list

I have define  attribute id as primary key of the table.......
Thanks for your help. Regards,Najm.

Najm,

> references age_list(id);
> And I get the following error:
> flipr=# alter table users
> flipr-# add constraint age_fk foreign key(age) references
> age_list(id);
> NOTICE:  ALTER TABLE ... ADD CONSTRAINT will create
> implicit trigger(s)
> for FOREIGN KEY check(s)
> ERROR:  <unnamed> referential integrity violation - key
> referenced from
> users not found in age_list

Simple ... you have values in the AGE column that are not in
the age_list table.  Thus you're in violation of the foriegn
key you're trying to establish.

-Josh Berkus

Josh Berkus wrote:

> Najm,
>
> > references age_list(id);
> > And I get the following error:
> > flipr=# alter table users
> > flipr-# add constraint age_fk foreign key(age) references
> > age_list(id);
> > NOTICE:  ALTER TABLE ... ADD CONSTRAINT will create
> > implicit trigger(s)
> > for FOREIGN KEY check(s)
> > ERROR:  <unnamed> referential integrity violation - key
> > referenced from
> > users not found in age_list
>
> Simple ... you have values in the AGE column that are not in
> the age_list table.  Thus you're in violation of the foriegn
> key you're trying to establish.
>
> -Josh Berkus

HI  Josh,
All values in age column of  are null..... I have no value there......
and I have specified to accetp nulls i.e.  I dont have constraint not
null on this particular column...
Najm